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Ontological Arguments

Ontological arguments are arguments, for the conclusion that God exists, from premises which are supposed to derive from some source other than observation of the world—e.g., from reason alone. In other words, ontological arguments are arguments from what are typically alleged to be none but analytic, a priori and necessary premises to the conclusion that God exists.

The first, and best-known, ontological argument was proposed by St. Anselm of Canterbury in the 11th century C.E. In his Proslogion , St. Anselm claims to derive the existence of God from the concept of a being than which no greater can be conceived . St. Anselm reasoned that, if such a being fails to exist, then a greater being—namely, a being than which no greater can be conceived, and which exists —can be conceived. But this would be absurd: nothing can be greater than a being than which no greater can be conceived. So a being than which no greater can be conceived—i.e., God—exists.

In the seventeenth century, René Descartes defended a family of similar arguments. For instance, in the Fifth Meditation , Descartes claims to provide a proof demonstrating the existence of God from the idea of a supremely perfect being. Descartes argues that there is no less contradiction in conceiving a supremely perfect being who lacks existence than there is in conceiving a triangle whose interior angles do not sum to 180 degrees. Hence, he supposes, since we do conceive a supremely perfect being—we do have the idea of a supremely perfect being—we must conclude that a supremely perfect being exists.

In the early eighteenth century, Gottfried Leibniz attempted to fill what he took to be a shortcoming in Descartes’ view. According to Leibniz, Descartes’ arguments fail unless one first shows that the idea of a supremely perfect being is coherent, or that it is possible for there to be a supremely perfect being. Leibniz argued that, since perfections are unanalysable, it is impossible to demonstrate that perfections are incompatible—and he concluded from this that all perfections can co-exist together in a single entity.

In more recent times, Kurt Gödel, Charles Hartshorne, Norman Malcolm and Alvin Plantinga have all presented much-discussed ontological arguments which bear interesting connections to the earlier arguments of St. Anselm, Descartes and Leibniz. Of these, the most interesting are those of Gödel and Plantinga; in these cases, however, it is unclear whether we should really say that these authors claim that the arguments are proofs of the existence of God.

Critiques of ontological arguments begin with Gaunilo, a contemporary of St. Anselm. Perhaps the best known criticisms of ontological arguments are due to Immanuel Kant, in his Critique of Pure Reason . Most famously, Kant claims that ontological arguments are vitiated by their reliance upon the implicit assumption that “existence” is a real predicate. However, as Bertrand Russell observed, it is much easier to be persuaded that ontological arguments are no good than it is to say exactly what is wrong with them. This helps to explain why ontological arguments have fascinated philosophers for almost a thousand years.

In various ways, the account provided to this point is rough, and susceptible of improvement. Sections 1–6 in what follows provide some of the requisite embellishments, though—as is usually the case in philosophy—there are many issues taken up here which could be pursued at much greater length. Sections 7–9 take up some of the central questions at a slightly more sophisticated level of discussion. Section 10 is a quick overview of very recent work on ontological arguments:

1. History of Ontological Arguments

2. taxonomy of ontological arguments, 3. characterisation of ontological arguments, 4. uses of ontological arguments, 5. objections to ontological arguments, 6. parodies of ontological arguments, 7. gödel’s ontological argument, 8. a victorious ontological argument, 9. st. anselm’s ontological argument, 10. ontological arguments in the 21st century, primary texts, other texts, other internet resources, related entries.

For a useful discussion of the history of ontological arguments in the modern period, see Harrelson 2009.

According to a modification of the taxonomy of Oppy 1995, there are eight major kinds of ontological arguments, viz:

  • definitional ontological arguments;
  • conceptual (or hyperintensional) ontological arguments;
  • modal ontological arguments;
  • Meinongian ontological arguments;
  • experiential ontological arguments;
  • mereological ontological arguments;
  • higher-order ontological arguments; and
  • ‘Hegelian’ ontological arguments;

Examples of all but the last follow. These are mostly toy examples. But they serve to highlight the deficiencies which more complex examples also share.

Note: No example is provided of a ‘Hegelian’ ontological argument. There is no extant discussion that states clearly the full set of premises of a ‘Hegelian’ ontological argument. (See Redding and Bubbio 2014 for recent discussion of this point.)

God is a being which has every perfection. (This is true as a matter of definition.) Existence is a perfection. Hence God exists.

I conceive of a being than which no greater can be conceived. If a being than which no greater can be conceived does not exist, then I can conceive of a being greater than a being than which no greater can be conceived—namely, a being than which no greater can be conceived that exists. I cannot conceive of a being greater than a being than which no greater can be conceived. Hence, a being than which no greater can be conceived exists.

It is possible that that God exists. God is not a contingent being, i.e., either it is not possible that God exists, or it is necessary that God exists. Hence, it is necessary that God exists. Hence, God exists. (See Malcolm 1960, Hartshorne 1965, and Plantinga 1974 for closely related arguments.)

[It is analytic, necessary and a priori that] Each instance of the schema “The F G is F ” expresses a truth. Hence the sentence “The existent perfect being is existent” expresses a truth. Hence, the existent perfect being is existent. Hence, God is existent, i.e. God exists. (The last step is justified by the observation that, as a matter of definition, if there is exactly one existent perfect being, then that being is God.)

The word ‘God’ has a meaning that is revealed in religious experience. The word ‘God’ has a meaning only if God exists. Hence, God exists. (See Rescher 1959 for a live version of this argument.)

I exist. Therefore something exists. Whenever a bunch of things exist, their mereological sum also exists. Therefore the sum of all things exists. Therefore God—the sum of all things—exists.

Say that a God-property is a property that is possessed by God in all and only those worlds in which God exists. Not all properties are God properties. Any property entailed by a collection of God-properties is itself a God-property. The God-properties include necessary existence, necessary omnipotence, necessary omniscience, and necessary perfect goodness. Hence, there is a necessarily existent, necessarily omnipotent, necessarily omniscient, and necessarily perfectly good being (namely, God).

Of course, this taxonomy is not exclusive: an argument can belong to several categories at once. Moreover, an argument can be ambiguous between a range of readings, each of which belongs to different categories. This latter fact may help to explain part of the curious fascination of ontological arguments. Finally, the taxonomy can be further specialised: there are, for example, at least four importantly different kinds of modal ontological arguments which should be distinguished. (See, e.g., Ross 1969 for a rather different kind of modal ontological argument.)

It is not easy to give a good characterisation of ontological arguments. The traditional characterisation involves the use of problematic notions—analyticity, necessity, and a priority —and also fails to apply to many arguments to which defenders have affixed the label “ontological”. (Consider, for example, the claim that I conceive of a being than which no greater can be conceived. This claim is clearly not analytic (its truth doesn’t follow immediately from the meanings of the words used to express it), nor necessary (I might never have entertained the concept), nor a priori (except perhaps in my own case, though even this is unclear—perhaps even I don’t know independently of experience that I have this concept.)) However, it is unclear how that traditional characterisation should be improved upon.

Perhaps one might resolve to use the label “ontological argument” for any argument which gets classified as “an ontological argument” by its proponent(s). This procedure would make good sense if one thought that there is a natural kind—ontological arguments—which our practice carves out, but for which is hard to specify defining conditions. Moreover, this procedure can be adapted as a pro tem stop gap: when there is a better definition to hand, that definition will be adopted instead. On the other hand, it seems worthwhile to attempt a more informative definition.

Focus on the case of ontological arguments for the conclusion that God exists. One characteristic feature of these arguments is the use which they make of “referential vocabulary”—names, definite descriptions, indefinite descriptions, quantified noun phrases, etc.—whose ontological commitments—for occurrences of this vocabulary in “referential position”—non-theists do not accept.

Theists and non-theists alike (can) agree that there is spatio-temporal, or causal, or nomic, or modal structure to the world (the basis for cosmological arguments); and that there are certain kinds of complexity of organisation, structure and function in the world (the basis for teleological arguments); and so on. But theists and non-theists are in dispute about whether there are perfect beings, or beings than which no greater can be conceived, or … ; thus, theists and non-theists are in dispute about the indirect subject matter of the premises of ontological arguments.

Of course, the premises of ontological arguments often do not deal directly with perfect beings, beings than which no greater can be conceived, etc.; rather, they deal with descriptions of, or ideas of, or concepts of, or the possibility of the existence of, these things. However, the basic point remains: ontological arguments require the use of vocabulary which non-theists should certainly find problematic when it is used in ontologically committing contexts (i.e not inside the scope of prophylactic operators—such as “according to the story” or “by the lights of theists” or “by the definition”—which can be taken to afford protection against unwanted commitments).

Note that this characterisation does not beg the question against the possibility of the construction of a successful ontological argument—i.e., it does not lead immediately to the conclusion that all ontological arguments are question-begging (in virtue of the ontologically committing vocabulary which they employ). For it may be that the vocabulary in question only gets used in premises under the protection of prophylactic operators (which ward off the unwanted commitments.) Of course, there will then be questions about whether the resulting arguments can possibly be valid—how could the commitments turn up in the conclusion if they are not there in the premises?—but those are further questions, which would remain to be addressed.

Before we turn to assessment of ontological arguments, we need to get clear about what the proper intended goals of ontological arguments can be. Suppose we think of arguments as having advocates and targets: when an advocate presents an argument to a target, the goal of the advocate is to bring about some change in the target. What might be the targets of ontological arguments, and what might be the changes that advocates of these arguments aim to bring about in those targets?

Here are some proposals; no doubt the reader can think of others:

  • The targets might be atheists, and the goal might be to turn them into theists.
  • The targets might be agnostics, and the goal might be to turn them into theists.
  • The targets might be theists, and the goal might be to improve the doxastic position of theists.
  • The targets might be professional philosophers, and the goal might be to advance understanding of the consequences of adopting particular logical rules, or treating existence as a real predicate, or allowing definitions to have existential import, or the like.
  • The targets might be undergraduate philosophy students, and the goal might be to give them some sufficiently frustrating examples on which to cut their critical teeth.

In the coming discussion, it will be supposed that the targets are atheists and agnostics, and that the goal is to turn them into theists. Suppose that an advocate presents an ontological argument to a target. What conditions must that arguments satisfy if it is fit for its intended purpose? A plausible suggestion is that, minimally, it should make the targets recognise that they have good reason to accept the conclusion of the argument that they did not recognise that they have prior to the presentation of the argument. Adopting this plausible suggestion provides the following criterion: a successful ontological argument is one that should make atheists and agnostics recognise that they have good reason to believe that God exists that they did not recognise that they have prior to the presentation of the argument. Note that this criterion has a normative dimension: it adverts to what atheists and agnostics should do when presented with the argument.

There is an important discussion to be had about whether we should suppose that the targets of ontological arguments are atheists and agnostics, and that the goal is to turn them into theists. However, it is simply beyond the scope of this entry to pursue that discussion here.

Objections to ontological arguments take many forms. Some objections are intended to apply only to particular ontological arguments, or particular forms of ontological arguments; other objections are intended to apply to all ontological arguments. It is a controversial question whether there are any successful general objections to ontological arguments.

One general criticism of ontological arguments which have appeared hitherto is this: none of them is persuasive , i.e., none of them provides those who do not already accept the conclusion that God exists—and who are reasonable, reflective, well-informed, etc.—with either a pro tanto reason or an all-things-considered reason to accept that conclusion. Any reading of any ontological argument which has been produced so far which is sufficiently clearly stated to admit of evaluation yields a result which is invalid, or possesses a set of premises which it is clear in advance that no reasonable, reflective, well-informed, etc. non-theists will accept, or has a benign conclusion which has no religious significance, or else falls prey to more than one of the above failings.

For each of the families of arguments introduced in the earlier taxonomy, we can give general reasons why arguments of that family fall under the general criticism. In what follows, we shall apply these general considerations to the exemplar arguments introduced in section 2.

(1) Definitional arguments: These are arguments in which ontologically committing vocabulary is introduced solely via a definition. An obvious problem is that claims involving that vocabulary cannot then be non-question-beggingly detached from the scope of that definition. (The inference from ‘By definition, God is an existent being’ to ‘God exists’ is patently invalid; while the inference to ‘By definition, God exists’ is valid, but uninteresting. In the example given earlier, the premises license the claim that, as a matter of definition, God possesses the perfection of existence. But, as just noted, there is no valid inference from this claim to the further claim that God exists.)

(2) Conceptual arguments: These are arguments in which ontologically committing vocabulary is introduced solely within the scope of hyperintensional operators (e.g. ‘believes that’, ‘conceives of’, etc.). Often, these operators have two readings, one of which can cancel ontological commitment, and the other of which cannot. On the reading which can give cancellation (as in the most likely reading of ‘John believes in Santa Claus’), the inference to a conclusion in which the ontological commitment is not cancelled will be invalid. On the reading which cannot cancel ontological commitment (as in that reading of ‘John thinks about God’ which can only be true if there is a God to think about), the premises are question-begging: they incur ontological commitments which non-theists reject. In our sample argument, the claim, that I conceive of an existent being than which no greater being can be conceived, admits of the two kinds of readings just distinguished. On the one hand, on the reading which gives cancellation, the inference to the conclusion that there is a being than which no greater can be conceived is plainly invalid. On the other hand, on the reading in which there is no cancellation, it is clear that this claim is one which no reasonable, etc. non-theist will accept: if you doubt that there is a being than which no greater can be conceived, then, of course, you doubt whether you can have thoughts about such a being.

(3) Modal arguments: These are arguments with premises which concern modal claims about God, i.e., claims about the possibility or necessity of God’s attributes and existence. Suppose that we agree to think about possibility and necessity in terms of possible worlds: a claim is possibly true just in case it is true in at least one possible world; a claim is necessarily true just in case it is true in every possible world; and a claim is contingent just in case it is true in some possible worlds and false in others. Some theists hold that God is a necessarily existent being, i.e., that God exists in every possible world; all non-theists reject the claim that God exists in the actual world. The sample argument consists, in effect, of two premises:

  • God exists in at least one possible world.
  • God exists in all possible worlds if God exists in any.

A minimally rational non-theist cannot accept both of these premises – they entail that God exists in every possible world whereas a minimally rational non-theist maintains that there is at least one possible world in which God does not exist. Given that a minimally rational non-theist says that there is at least one possible world in which God does not exist, such a non-theist can offer a parallel counterargument with the following two premises:

  • God fails to exist in at least one possible world.

These premises entail that God exists in no possible world, and hence that God does not exist in the actual world. Considered together, the argument and the counterargument just mentioned plainly do not give anyone a reason to prefer theism to non-theism, and nor do they give anyone a reason to prefer non-theism to theism. So the sample argument is unsuccessful: it doesn’t supply an all-things-considered reason to prefer theism to non-theism (just as the counterargument doesn’t supply an all-things-considered reason to prefer non-theism to theism).

(4) Meinongian arguments: These are arguments which depend somehow or other on Meinongian theories of objects. Consider the schema ‘The F G is F ’. Naive Meinongians will suppose that if F is instantiated with any property, then the result is true (and, quite likely, necessary, analytic and a priori). So, for example, the round square is round; the bald current King of France is bald; and so on. However, more sophisticated Meinongians will insist that there must be some restriction on the substitution instances for F, in order to allow one to draw the obvious and important ontological distinction between the following two groups: {Bill Clinton, the sun, the Eiffel Tower} and {Santa Claus, Mickey Mouse, the round square}. Choice of vocabulary here is controversial: Let us suppose (for the sake of example) that the right thing to say is that the former things exist and the latter do not. Under this supposition, ‘existent’ will not be a suitable substitution instance for F—obviously, since we all agree that there is no existent round square. Of course, nothing hangs on the choice of ‘existent’ as the crucial piece of vocabulary. The point is that non-theists are not prepared to include god(s) in the former group of objects—and hence will be unpersuaded by any argument which tries to use whatever vocabulary is used to discriminate between the two classes as the basis for an argument that god(s) belong to the former group. (Cognoscenti will recognise that the crucial point is that Meinongian ontological arguments fail to respect the distinction between nuclear (assumptible, characterising) properties and non-nuclear (non-assumptible, non-characterising) properties. It should, of course, be noted that neither Meinong, nor any of his well-known modern supporters—e.g. Terence Parsons, Richard Sylvan—ever endorses a Meinongian ontological argument; and it should also be noted that most motivate the distinction between nuclear and non-nuclear properties in part by a need to avoid Meinongian ontological arguments. The reason for calling these arguments “Meinongian” is that they rely on quantification over—or reference to—non-existent objects; there is no pejorative intent in the use of this label.)

(5) Experiential arguments: These are arguments which try to make use of ‘externalist’ or ‘object-involving’ accounts of content. It should not be surprising that they fail. After all, those accounts of content need to have something to say about expressions which fail to refer (‘Santa Claus’, ‘phlogiston’, etc.). But, however the account goes, non-theists will insist that expressions which purport to refer to god(s) should be given exactly the same kind of treatment.

(6) Mereological arguments: Those who dislike mereology will not be impressed by these arguments. However, even those who accept principles of unrestricted composition—i.e., who accept principles which claim, e.g., that, whenever there are some things, there is something which is the sum or fusion of all of those things—need not be perturbed by them: for it is plausible to think that the conclusions of these arguments have no religious significance whatsoever—they are merely arguments for, e.g., the existence of the physical universe.

(7) Higher-Order arguments: The key to these arguments is the observation that any collection of properties, that (a) does not include all properties and (b) is closed under entailment, is possibly jointly instantiated. If it is impossible that God exists — as all who deny that God exists suppose, on the further assumption that, were God to exist, God would exist of necessity — then it cannot be true both that the God-properties are closed under entailment and that there are properties that are not God-properties. Those who take themselves to have good independent reason to deny that there are any gods will take themselves to have good independent reason to deny that there are God-properties that form a non-trivial collection that is closed under entailment.

Even if the forgoing analyses are correct, it is important to note that no argument has been given for the conclusion that no ontological argument can be successful. Even if all of the kinds of arguments produced to date are pretty clearly unsuccessful—i.e., not such as ought to give non-theists reason to accept the conclusion that God exists—it remains an open question whether there is some other kind of hitherto undiscovered ontological argument which does succeed. (Perhaps it is worth adding here that there is fairly widespread consensus, even amongst theists, that no known ontological arguments for the existence of God are persuasive. Most categories of ontological argument have some actual defenders; but none has a large following.)

Many other objections to (some) ontological arguments have been proposed. All of the following have been alleged to be the key to the explanation of the failure of (at least some) ontological arguments: (1) existence is not a predicate (see, e.g., Kant, Smart 1955, Alston 1960); (2) the concept of god is meaningless/incoherent/ inconsistent (see, e.g., Findlay 1949); (3) ontological arguments are ruled out by “the missing explanation argument” (see Johnston 1992; (4) ontological arguments all trade on mistaken uses of singular terms (see, e.g., Barnes 1972; (5) existence is not a perfection (see almost any textbook in philosophy of religion); (6) ontological arguments presuppose a Meinongian approach to ontology (see, e.g., Dummett 1993); and (7) ontological arguments are question-begging, i.e., presuppose what they set out to prove (see, e.g., Rowe 1989). There are many things to say about these objections: the most important point is that almost all of them require far more controversial assumptions than non-theists require in order to be able to reject ontological arguments with good conscience. Trying to support most of these claims merely in order to beat up on ontological arguments is like using a steamroller to crack a nut (in circumstances in which one is unsure that one can get the steamroller to move!).

Of course, all of the above discussion is directed merely to the claim that ontological arguments are not dialectically efficacious—i.e., they give reasonable non-theists no reason to change their views. It might be wondered whether there is some other use which ontological arguments have—e.g., as Plantinga claims, in establishing the reasonableness of theism. This seems unlikely. After all, at best these arguments show that certain sets of sentences (beliefs, etc.) are inconsistent—one cannot reject the conclusions of these arguments while accepting their premises. But the arguments themselves say nothing about the reasonableness of accepting the premisses. So the arguments themselves say nothing about the (unconditional) reasonableness of accepting the conclusions of these arguments. Those who are disposed to think that theism is irrational need find nothing in ontological arguments to make them change their minds (and those who are disposed to think that theism is true should take no comfort from them either).

Positive ontological arguments—i.e., arguments FOR the existence of god(s)—invariably admit of various kinds of parodies, i.e., parallel arguments which seem at least equally acceptable to non-theists, but which establish absurd or contradictory conclusions. For many positive ontological arguments, there are parodies which purport to establish the non-existence of god(s); and for many positive ontological arguments there are lots (usually a large infinity!) of similar arguments which purport to establish the existence of lots (usually a large infinity) of distinct god-like beings. Here are some modest examples:

(1) By definition, God is a non-existent being who has every (other) perfection. Hence God does not exist.

(2) I conceive of a being than which no greater can be conceived except that it only ever creates n universes. If such a being does not exist, then we can conceive of a greater being—namely, one exactly like it which does exist. But I cannot conceive of a being which is greater in this way. Hence, a being than which no greater can be conceived except that it only ever creates n universes exists.

(3) It is possible that God does not exist. God is not a contingent being, i.e., either it is not possible that God exists, or it is necessary that God exists. Hence it is not possible that God exists. Hence God does not exist.

(4) It is analytic, necessary, and a priori that the F G is F . Hence, the existent perfect being who creates exactly n universes is existent. Hence the perfect being who creates exactly n universes exists.

There are many kinds of parodies of Ontological Arguments. The aim is to construct arguments which non-theists can reasonably claim to have no more reason to accept than the original Ontological Arguments themselves. Of course, theists may well be able to hold that the originals are sound, and the parodies not—but that is an entirely unrelated issue. (All theists—and no non-theists—should grant that the following argument is sound, given that the connectives are to be interpreted classically: “Either 2+2=5, or God exists. Not 2+2=5. Hence God exists.” This argument contributes nothing positive to any case for theism, just as the argument “Either 2+2=5, or God does not exist. Not 2+2=5. Hence God does not exist.” contributes nothing positive to the case for non-theism.)

There are many parodic discussions of Ontological Arguments in the literature. See, for example, the parody provided by Raymond Smullyan (1984), in which the argument is attributed to “the unknown Dutch theologian van Dollard”. A relatively recent addition to the genre is described in Grey 2000, though the date of its construction is uncertain. It is the work of Douglas Gasking, one-time Professor of Philosophy at the University of Melbourne (with emendations by William Grey and Denis Robinson):

  • The creation of the world is the most marvellous achievement imaginable.
  • The merit of an achievement is the product of (a) its intrinsic quality, and (b) the ability of its creator.
  • The greater the disability or handicap of the creator, the more impressive the achievement.
  • The most formidable handicap for a creator would be non-existence.
  • Therefore, if we suppose that the universe is the product of an existent creator, we can conceive a greater being—namely, one who created everything while not existing.
  • An existing God, therefore, would not be a being than which a greater cannot be conceived, because an even more formidable and incredible creator would be a God which did not exist.
  • (Hence) God does not exist.

This parody—at least in its current state—is inferior to other parodies in the literature, including the early parodies of Gaunilo and Caterus. To mention but one difficulty, while we might suppose that it would be a greater achievement to create something if one did not exist than if one did exist, it doesn’t follow from this that a non-existent creator is greater ( qua being) than an existent creator. Perhaps it might be replied that this objection fails to take the first premise into account: if the creation of the world really is “the most marvellous achievement imaginable”, then surely there is some plausibility to the claim that the creator must have been non-existent (since that would make the achievement more marvellous than it would otherwise have been). But what reason is there to believe that the creation of the world is “the most marvellous achievement imaginable”, in the sense which is required for this argument? Surely it is quite easy to imagine even more marvellous achievements—e.g., the creation of many worlds at least as good as this one! (Of course, one might also want to say that, in fact, one cannot conceive of a non-existent being’s actually creating something: that is literally inconceivable. Etc.)

Chambers 2000 and Siegwart 2014 provide interesting recent discussions of Gaunilo’s parody of the Proslogion II argument.

There is a small, but steadily growing, literature on the ontological arguments which Gödel developed in his notebooks, but which did not appear in print until well after his death. These arguments have been discussed, annotated and amended by various leading logicians: the upshot is a family of arguments with impeccable logical credentials. (Interested readers are referred to Sobel 1987, Anderson 1990, Adams 1995b, and Hazen 1999 for the history of these arguments, and for the scholarly annotations and emendations.) Here, we give a brief presentation of the version of the argument which is developed by Anderson, and then make some comments on that version. This discussion follows the presentation and discussion in Oppy 1996, 2000.

Definition 1: x is God-like if and only if x has as essential properties those and only those properties which are positive Definition 2: A is an essence of x if and only if for every property B , x has B necessarily if and only if A entails B Definition 3: x necessarily exists if and only if every essence of x is necessarily exemplified Axiom 1: If a property is positive, then its negation is not positive. Axiom 2: Any property entailed by—i.e., strictly implied by—a positive property is positive Axiom 3: The property of being God-like is positive Axiom 4: If a property is positive, then it is necessarily positive Axiom 5: Necessary existence is positive Axiom 6: For any property P , if P is positive, then being necessarily P is positive. Theorem 1: If a property is positive, then it is consistent, i.e., possibly exemplified. Corollary 1: The property of being God-like is consistent. Theorem 2: If something is God-like, then the property of being God-like is an essence of that thing. Theorem 3: Necessarily, the property of being God-like is exemplified.

Given a sufficiently generous conception of properties, and granted the acceptability of the underlying modal logic, the listed theorems do follow from the axioms. (This point was argued in detail by Dana Scott, in lecture notes which circulated for many years and which were transcribed in Sobel 1987 and published in Sobel 2004. It is also made by Sobel, Anderson, and Adams.) So, criticisms of the argument are bound to focus on the axioms, or on the other assumptions which are required in order to construct the proof.

Some philosophers have denied the acceptability of the underlying modal logic. And some philosophers have rejected generous conceptions of properties in favour of sparse conceptions according to which only some predicates express properties. But suppose that we adopt neither of these avenues of potential criticism of the proof. What else might we say against it?

One important point to note is that no definition of the notion of “positive property” is supplied with the proof. At most, the various axioms which involve this concept can be taken to provide a partial implicit definition. If we suppose that the “positive properties” form a set, then the axioms provide us with the following information about this set:

  • If a property belongs to the set, then its negation does not belong to the set.
  • The set is closed under entailment.
  • The property of having as essential properties just those properties which are in the set is itself a member of the set.
  • The set has exactly the same members in all possible worlds.
  • The property of necessary existence is in the set.
  • If a property is in the set, then the property of having that property necessarily is also in the set.

On Gödel’s theoretical assumptions, we can show that any set which conforms to (1)–(6) is such that the property of having as essential properties just those properties which are in that set is exemplified. Gödel wants us to conclude that there is just one intuitive, theologically interesting set of properties which is such that the property of having as essential properties just the properties in that set is exemplified. But, on the one hand, what reason do we have to think that there is any theologically interesting set of properties which conforms to the Gödelian specification? And, on the other hand, what reason do we have to deny that, if there is one set of theologically interesting set of properties which conforms to the Gödelian specification, then there are many theologically threatening sets of properties which also conform to that specification?

In particular, there is some reason to think that the Gödelian ontological argument goes through just as well—or just as badly—with respect to other sets of properties (and in ways which are damaging to the original argument). Suppose that there is some set of independent properties { I , G 1 , G 2 , …} which can be used to generate the set of positive properties by closure under entailment and “necessitation”. (“Independence” means: no one of the properties in the set is entailed by all the rest. “Necessitation” means: if P is in the set, then so is necessarily having P . I is the property of having as essential properties just those properties which are in the set. G 1 , G 2 , … are further properties, of which we require at least two.) Consider any proper subset of the set { G 1 , G 2 , …}—{ H 1 , H 2 , …}, say—and define a new generating set { I *, H 1 , H 2 , …}, where I * is the property of having as essential properties just those properties which are in the newly generated set. A “proof” parallel to that offered by Gödel “establishes” that there is a being which has as essential properties just those properties in this new set. If there are as few as 7 independent properties in the original generating set, then we shall be able to establish the existence of 720 distinct“God-like” creatures by the kind of argument which Gödel offers. (The creatures are distinct because each has a different set of essential properties.)

Even if the above considerations are sufficient to cast doubt on the credentials of Gödel’s “proof”, they do not pinpoint where the “proof” goes wrong. If we accept that the role of Axioms 1, 2, 4, and 6 is really just to constrain the notion of “positive property” in the right way—or, in other words, if we suppose that Axioms 1, 2, 4, and 6 are “analytic truths” about “positive properties”—then there is good reason for opponents of the “proof” to be sceptical about Axioms 3 and 5. Kant would not have been happy with Axiom 5; and there is at least some reason to think that whether the property of being God-like is “positive” ought to depend upon whether or not there is a God-like being.

For detailed recent discussion of Gödel’s argument, see Kovac (2003), Pruss (2009) (2018), and Swietorzecka (2016).

The “victorious” modal ontological argument of Plantinga 1974 goes roughly as follows: Say that an entity possesses “maximal excellence” if and only if it is omnipotent, omniscient, and morally perfect. Say, further, that an entity possesses “maximal greatness” if and only if it possesses maximal excellence in every possible world—that is, if and only if it is necessarily existent and necessarily maximally excellent. Then consider the following argument:

  • There is a possible world in which there is an entity which possesses maximal greatness.
  • (Hence) There is an entity which possesses maximal greatness.

Under suitable assumptions about the nature of accessibility relations between possible worlds, this argument is valid: from it is possible that it is necessary that p , one can infer that it is necessary that p . Setting aside the possibility that one might challenge this widely accepted modal principle, it seems that opponents of the argument are bound to challenge the acceptability of the premise.

And, of course, they do. Let’s just run the argument in reverse.

  • There is no entity which possesses maximal greatness.
  • (Hence) There is no possible world in which there is an entity which possesses maximal greatness.

Plainly enough, if you do not already accept the claim that there is an entity which possesses maximal greatness, then you won’t agree that the first of these arguments is more acceptable than the second. So, as a proof of the existence of a being which possesses maximal greatness, Plantinga’s argument seems to be a non-starter.

Perhaps somewhat surprisingly, Plantinga himself agrees: the “victorious” modal ontological argument is not a proof of the existence of a being which possesses maximal greatness. But how, then, is it “victorious”? Plantinga writes: “Our verdict on these reformulated versions of St. Anselm’s argument must be as follows. They cannot, perhaps, be said to prove or establish their conclusion. But since it is rational to accept their central premise, they do show that it is rational to accept that conclusion” (Plantinga 1974, 221).

It is clear that Plantinga’s argument does not show what he claims that it shows. Consider, again, the argument: “Either God exists, or 2+2=5. It is not the case that 2+2=5. So God exists.” It is a mistake for a theist to say: “Since the premise is true (and the argument is valid), this argument shows that the conclusion of the argument is true ”, just as it is a mistake for a non-theist to say that the argument “Either God does not exist, or 2+2=5. It is not the case that 2+2=5. So God does not exist.” shows that God does not exist. Similarly, it is a mistake for a theist to say: “Since it is rational to accept the premises (and the argument is valid), this argument shows that it is rational to accept the claim that God exists”, just as it is a mistake for the non-theist to say: “Since it is rational to accept the premises of the non-theistic argument (and that argument is valid), the non-theistic argument shows that it is rational to accept the claim that God does not exist”. While there is room for dispute about exactly why all of this is so, it is plausible to say that, in each case, any even minimally rational person who has doubts about the claimed status of the conclusion of the argument will have exactly the same doubts about the claimed status of the premise. If, for example, I doubt that it is rational to accept the claim that God exists, then you can be quite sure that I will doubt that it is rational to accept the claim that either 2+2=5 or God exists. But the very same point can be made about Plantinga’s argument: anyone with even minimal rationality who understands the premise and the conclusion of the argument, and who has doubts about the claim that it is rationally permissible to believe that there is an entity which possesses maximal greatness, will have exactly the same doubts about the claim that it is rationally permissible to believe that there is a possible world in which there is an entity which possesses maximal greatness.

For further discussion of Plantinga’s argument, see—for example—Adams 1988, Chandler 1993, Oppy 1995 (70–78, 248–259), Rasmussen (2018), Tooley 1981, and van Inwagen 1977).

There is an enormous literature on the material in Proslogion II-III . Some commentators deny that St. Anselm tried to put forward any proofs of the existence of God. Even among commentators who agree that St. Anselm intended to prove the existence of God, there is disagreement about where the proof is located. Some commentators claim that the main proof is in Proslogion II , and that the rest of the work draws out corollaries of that proof (see, e.g., Charlesworth 1965). Other commentators claim that the main proof is in Prologion III , and that the proof in Proslogion II is merely an inferior first attempt (see, e.g., Malcolm 1960). Yet other commentators claim that there is a single proof which spans at least Proslogion II-III —see, e.g., Campbell 1976 and, perhaps, the entire work—see, e.g., La Croix 1972. In what follows, we ignore this aspect of the controversy about the Proslogion . Instead, we focus just on the question of the analysis of the material in Proslogion II on the assumption that there is an independent argument for the existence of God which is given therein.

Here is one translation of the crucial part of Proslogion II (due to William Mann (1972, 260–1); alternative translations can be found in Barnes 1972, Campbell 1976, Charlesworth 1965, and elsewhere):

Thus even the fool is convinced that something than which nothing greater can be conceived is in the understanding, since when he hears this, he understands it; and whatever is understood is in the understanding. And certainly that than which a greater cannot be conceived cannot be in the understanding alone. For if it is even in the understanding alone, it can be conceived to exist in reality also, which is greater. Thus if that than which a greater cannot be conceived is in the understanding alone, then that than which a greater cannot be conceived is itself that than which a greater can be conceived. But surely this cannot be. Thus without doubt something than which a greater cannot be conceived exists, both in the understanding and in reality.

There have been many ingenious attempts to find an argument which can be expressed in modern logical formalism, which is logically valid, and which might plausibly be claimed to be the argument which is expressed in this passage. To take a few prime examples, Adams 1971, Barnes 1972 and Oppenheimer and Zalta 1991 have all produced formally valid analyses of the argument in this passage. We begin with a brief presentation of each of these analyses, preceded by a presentation of the formulation of the argument given by Plantinga 1967, and including a presentation of some of the formulations of Lewis 1970. (Chambers 2000 works with the analysis of Adams 1971.)

9.1 Formulation 1

God exists in the understanding but not in reality. (Assumption for reductio )

Existence in reality is greater than existence in the understanding alone. (Premise)

A being having all of God’s properties plus existence in reality can be conceived. (Premise)

A being having all of God’s properties plus existence in reality is greater than God. (From (1) and (2).)

A being greater than God can be conceived. (From (3) and (4).)

It is false that a being greater than God can be conceived. (From definition of “God”.)

Hence, it is false that God exists in the understanding but not in reality. (From (1), (5), (6).)

God exists in the understanding. (Premise, to which even the Fool agrees.)

Hence God exists in reality. (From (7), (8).)

See Plantinga 1967.

9.2 Formulation 2

The Fool understands the expression “the being than which no greater can be conceived”. (Premise)

If a person understands an expression “ b ”, then b is in that person’s understanding. (Premise)

If a thing is in a person’s understanding, then the person can conceive of that thing’s existing in reality. (Premise)

Each thing which exists in reality is greater than any thing which exists only in the understanding. (Premise)

If a person can conceive of something, and that thing entails something else, then the person can also conceive of that other thing. (Premise)

If a person can conceive that a specified object has a given property, then that person can conceive that something or other has that property. (Premise)

Hence the being than which no greater can be conceived exists in reality. (From (1)-(6), by a complex series of steps here omitted.)

See Barnes 1972.

9.3 Formulation 3

There is a thing x , and a magnitude m , such that x exists in the understanding, m is the magnitude of x , and it it not possible that there is a thing y and a magnitude n such that n is the magnitude of y and n > m . (Premise)

For any thing x and magnitude m , if x exists in the understanding, m is the magnitude of x , and it is not possible that there is a thing y and magnitude n such that n is the magnitude of y and n > m , then it is possible that x exists in reality. (Premise)

For any thing x and magnitude m , if m is the magnitude of x , and it it not possible that there is a thing y and a magnitude n such that n is the magnitude of y and n > m , and x does not exist in reality, then it is not possible that if x exists in reality then there is a magnitude n such that n is greater than m and n is the magnitude of x . (Premise)

(Hence) There is a thing x and a magnitude m such that x exist in the understanding, and x exists in reality, and m is the magnitude of x , and it it not possible that there is a thing y and a magnitude n such that n is the magnitude of y and n > m . (From 1, 2, 3)

See Adams 1971.

9.4 Formulation 4

For any understandable being x , there is a world w such that x exists in w . (Premise)

For any understandable being x , and for any worlds w and v , if x exists in w , but x does not exist in v , then the greatness of x in w exceeds the greatness of x in v . (Premise)

There is an understandable being x such that for no world w and being y does the greatness of y in w exceed the greatness of x in the actual world. (Premise)

(Hence) There is a being x existing in the actual world such that for no world w and being y does the greatness of y in w exceed the greatness of x in the actual world. (From (1)-(3).)

See Lewis 1970.

Lewis also suggests an alternative to (3) which yields a valid argument:

(3′) There is an understandable being x such that for no worlds v and w and being y does the greatness of y in w exceed the greatness of x in v .

and two alternatives to (3)—not presented here—which yield invalid arguments. (Of course, these further two alternatives are crucial to Lewis’ overall analysis of the passage: essentially, Lewis suggests that Anselm equivocates between an invalid argument with plausible premises and a valid argument with question-begging premises. In this respect, Lewis’ analysis is quite different from the other analyses currently under discussion.)

9.5 Formulation 5

There is (in the understanding) something than which there is no greater. (Premise)

(Hence) There is (in the understanding) a unique thing than which there is no greater. (From (1), assuming that the “greater-than” relation is connected.)

(Hence) There is (in the understanding) something which is the thing than which there is no greater. (From (2), by a theorem about descriptions.)

(Hence) There is (in the understanding) nothing which is greater than the thing than which there is no greater. (From (3), by another theorem about descriptions.)

If that thing than which there is no greater does not exist (in reality), then there is (in the understanding) something which is greater than that thing than which there is no greater. (Premise)

(Hence) That thing than which there is no greater exists (in reality). (From (4) and (5).)

(Hence) God exists. (From (6).)

See Oppenheimer and Zalta 1991.

Oppenheimer and Zalta 2011 provides a “simplified” version of this argument, in which the number of controversial assumptions is reduced. Since they also provide a clear reason for thinking that this new version of the argument is not persuasive, it won't be considered further here.

9.6 Critical Appraisal

Considered as interpretations of the argument presented in the Proslogion , these formulations are subject to various kinds of criticisms.

First , the modal interpretations of Lewis 1970 and Adams 1971 don’t square very well with the rest of the Proslogion : the claim that “being than which no greater can be conceived” should be read as “being than which no greater is possible” would have us render the claim of Proslogion 15 to be that God is a being greater than any which is possible. And that is surely a bad result.

Second , the Meinongian interpretations of Barnes 1972, Adams 1971 and Oppenheimer and Zalta 1991 produce arguments which, given the principles involved, could easily be much simplified, and which are obviously vulnerable to Gaunilo-type objections.

Consider, for example, the case of Oppenheimer and Zalta. They have Anselm committed to the claim that if anyone can understand the phrase “that than which F ”, then there is something in the understanding such that F (see their footnote 25); and they also have him committed to the claim that if there is something which is the F -thing, then it—i.e., the F -thing—has the property F (see page 7). Plainly though, if Anselm is really committed to these principles, then he could hardly fail to be committed to the more general principles: (1) if anyone can understand the phrase “an F ”, then there is at least one F -thing in the understanding; and (2) if there are some things which are the F -things, then they—i.e., the F -things—must have the property F . (It would surely be absurd to claim that Anselm is only committed to the less general principles: what could possibly have justified the restrictions to the special cases?)

But, then, mark the consequences. We all understand the expression “an existent perfect being”. So, by the first claim, there is at least one existent perfect being in the understanding. And, by the second claim, any existent perfect being is existent. So, from these two claims combined, there is—in reality—at least one existent perfect being.

This argument gives Anselm everything that he wants, and very much more briefly. (The Proslogion goes on and on, trying to establish the properties of that than which no greater can be conceived. How much easier if we can just explicitly build all of the properties which want to “derive” into the initial description.) So, if Anselm really were committed to the principles which Oppenheimer and Zalta appear to attribute to him, it is hard to understand why he didn’t give the simpler argument. And, of course, it is also hard to understand why he didn’t take Gaunilo’s criticism. After all, when it is set out in this way, it is obvious that the argument proves far too much.

Third , some of the arguments have Anselm committed to claims about greatness which do not seem to correspond with what he actually says. The natural reading of the text is that, if two beings are identical save that one exists only in the understanding and the other exists in reality as well, then the latter is greater than the former. But Barnes 1971, for example, has Anselm committed to the much stronger claim that any existing thing is greater than every non-existent thing.

Given these kinds of considerations, it is natural to wonder whether there are better interpretations of Proslogion II according to which the argument in question turns out NOT to be logically valid. Here is a modest attempt to provide such an analysis:

We start with the claim that the Fool understands the expression “being than which no greater can be conceived”, i.e., even the Fool can entertain the idea or possess the concept of a being than which no greater can be conceived. Now, entertaining this idea or possessing this concept requires the entertainer or possessor to recognise certain relationships which hold between given properties and the idea or concept in question. For example, given that you possess the concept of, or entertain the idea of, a smallest really existent Martian, it follows that you must recognise some kind of connection between the properties of being a Martian, really existing, and being smaller than other really existing Martians, and the concept or idea in question.

Following Anselm, we might say that, since you understand the expression “smallest really existent Martian”, there is, in your understanding, at least one smallest really existent Martian. (Or, apparently following Descartes, one might say that real existence is “part of”—or “contained in”—the idea of a smallest really existent Martian.) However, in saying this, it must be understood that we are not actually predicating properties of anything: we aren’t supposing that there is something which possesses the properties of being a Martian, really existing, and being no larger than any other Martian. (After all, we can safely suppose, we don’t think that any Martians really exist.) In other words, we must be able to have the concept of, or entertain the idea of, a smallest really existing Martian without believing that there really are any smallest Martians. Indeed, more strongly, we must be able to entertain the concept of a smallest really existent Martian—and to recognise that the property of “really existing” is part of this concept—while nonetheless maintaining that there are no smallest existent Martians.

It will be useful to introduce vocabulary to mark the point which is being made here. We could, for instance, distinguish between the properties which are encoded in an idea or concept, and the properties which are attributed in positive atomic beliefs which have that idea or concept as an ingredient. The idea “really existent Santa Claus” encodes the property of real existence; but it is perfectly possible to entertain this idea without attributing real existence to Santa Claus, i.e., without believing that Santa Claus really exists.

We can then apply this distinction to Anselm’s argument. On the one hand, the idea “being than which no greater can be conceived” encodes the property of real existence—this is what the reductio argument establishes (if it establishes anything at all). On the other hand, it is perfectly possible to entertain the idea of a being than which no greater can be conceived—and to recognise that this idea encodes the property of real existence—without attributing real existence to a being than which no greater can be conceived, i.e., without believing that a being than which no greater can be conceived really exists.

Of course, the argument which Anselm actually presents pays no attention to this distinction between encoding and attributing—i.e., between entertaining an idea and holding a belief—and nor does it pay attention to various other niceties. We begin from the point that the Fool entertains the idea of that than which no greater can be conceived (because the Fool understands the words “that than which no greater can be conceived”). From this, we move quickly to the claim that even the Fool is “convinced”—i.e., believes—that that than which no greater can be conceived possesses the property of existing in the understanding. And then the reductio argument is produced to establish that that than which no greater can be conceived cannot exist only in the understanding but must also possess the property of existing in reality as well (and all mention of the Fool, and what it is that the Fool believes, disappears).

As it stands, this is deeply problematic. How are we supposed to regiment the references to the Fool in the argument? Is the reductio argument supposed to tell us something about what even the Fool believes, or ought to believe? Are the earlier references to the Fool supposed to be inessential and eliminable? How are we so much as to understand the claim that even the Fool believes that that than which no greater can be conceived exists in the understanding? And how do we get from the Fool’s understanding the words “that than which no greater can be conceived” to his believing that that than which no greater can be conceived possesses the property of existing in the understanding?

Following the earlier line of thought, it seems that the argument might go something like this:

(Even) the Fool has the concept of that than which no greater can be conceived.

(Hence) (Even) the Fool believes that that than which no greater can be conceived exists in the understanding.

No one who believes that that than which no greater can be conceived exists in the understanding can reasonably believe that that than which no greater can be conceived exists only in the understanding.

(Hence) (Even) the Fool cannot reasonably deny that that than which no greater can be conceived exists in reality

(Hence) That than which no greater can be conceived exists in reality.

While this is not a good argument, it could appear compelling to one who failed to attend to the distinction between entertaining ideas and holding beliefs and who was a bit hazy on the distinction between the vehicles of belief and their contents. When the Fool entertains the concept of that than which no greater can be conceived he recognises that he is entertaining this concept (i.e., he believes that he is entertaining the concept of that than which no greater can be conceived—or, as we might say, that the concept is in his understanding). Conflating the concept with its object, this gives us the belief that than which no greater can be conceived possesses the property of existing in the understanding. Now, suppose as hypothesis for reductio , that we can reasonably believe that that than which no greater can be conceived possesses the property of existing only in the understanding. Ignoring the distinction between entertaining ideas and holding beliefs, this means that we when we entertain the idea of that than which no greater can be conceived, we entertain the idea of a being which exists only in the understanding. But that is absurd: when we entertain the idea of that than which no greater can be conceived, our idea encodes the property of existing in reality. So there is a contradiction, and we can conclude that, in order to be reasonable, we must believe that that than which no greater can be conceived exists in reality. But if any reasonable person must believe that that than which no greater can be conceived exists in reality, then surely it is the case that that than which no greater can be conceived exists in reality. And so we are done.

No doubt this suggestion about the interpretation of Anselm’s argument is deficient in various ways. However, the point of including it is illustrative rather than dogmatic. In the literature, there has been great resistance to the idea that the argument which Anselm gives is one which modern logicians would not hesitate to pronounce invalid. But it is very hard to see why there should be this resistance. (Certainly, it is not something for which there is much argument in the literature.) The text of the Proslogion is so rough, and so much in need of polishing, that we should not be too quick to dismiss the suggestion that Anselm’s argument is rather more like the argument most recently sketched than it is like the logically valid demonstrations provided by commentators such as Barnes, Adams, and Oppenheimer and Zalta. (For a more complex analysis of Proslogion II that has it yielding a valid argument, see Hinst 2014.)

Many recent discussions of ontological arguments are in compendiums, companions, encyclopedias, and the like. So, for example, there are review discussions of ontological arguments in: Leftow 2005, Matthews 2005, Lowe 2007, Oppy 2007, and Maydole 2009. While the ambitions of these review discussions vary, many of them are designed to introduce neophytes to the arguments and their history. Given the current explosion of enthusiasm for compendiums, companions, encyclopedias, and the like, in philosophy of religion, it is likely that many more such discussions will appear in the immediate future.

Some recent discussions of ontological arguments have been placed in more synoptic treatments of arguments about the existence of God. So, for example, there are extended discussions of ontological arguments in Everitt 2004, Sobel 2004, and Oppy 2006. Sobel’s examination of ontological arguments is exemplary. He provides one chapter on ‘classical ontological arguments’: Anselm, Descartes, Spinoza, and Kant’s critique of ontological arguments; one chapter on ‘modern modal ontological arguments’: Hartshorne, Malcolm and Plantinga; and one chapter on Gödel’s ontological argument. His analyses are very careful, and make heavy use of the tools of modern philosophical logic.

There has been one recent monograph devoted exclusively to the analysis of ontological arguments: Dombrowski 2006. Dombrowski is a fan of Hartshorne: the aim of his book is to defend the claim that Hartshorne’s ontological argument is a success. While Dombrowski’s book is a useful addition to the literature because of the scope of its discussion of ontological arguments—for example, it contains a chapter on Rorty on ontological arguments, and another chapter on John Taylor on ontological arguments—even reviewers sympathetic to process theism have not been persuaded that it makes a strong case for its central thesis.

Szatkowski (2012) is a recent collection of papers on ontological arguments. A significant proportion of papers in this collection take up technical questions about logics that support ontological derivations. (Those interested in technical questions may also be interested in the topic taken up in Oppenheimer and Zalta (2011) and Gorbacz (2012).) The most recent collection is Oppy (2018).

Finally, there has been some activity in journals. The most significant of these pieces is Millican 2004, the first article on ontological arguments in recent memory to appear in Mind . Millican argues for a novel interpretation of Anselm’s argument, and for a new critique of ontological arguments deriving from this interpretation. Needless to say, both the interpretation and the critique are controversial, but they are also worthy of attention. Among other journal articles, perhaps the most interesting is Pruss 2010, which provides a novel defence of the key possibility premise in modal ontological arguments. There is also a chain of papers in Analysis initiated by Matthews and Baker (2010)

Relatively recent work on ontological arguments by women includes: Anscombe (1993), Antognazza (2018), Crocker (1972), Diamond (1977), Ferreira (1983), Garcia (2008), [Haight and] Haight (1970), [Matthews and] Baker (2011), Wilson (1978) and Zagzebski (1984).

  • Anselm, St., Proslogion , in St. Anselm’s Proslogion , M. Charlesworth (ed.), Oxford: OUP, 1965 [ Available online , in the Internet Medieval Sourcebook, Paul Halsall (ed.), Fordham University Center for Medieval Studies, translation by David Burr].
  • Aquinas, T., Summa Theologica , 1272, literally translated by Fathers of the English Dominican Province, London: Burn, Oates & Washbourne, 1920 [ Available online , in the Internet Medieval Sourcebook, Paul Halsall (ed.), Fordham University Center for Medieval Studies, translation by David Burr].
  • Ayer, A., Language, Truth and Logic , second edition, London: Gollancz, 1948.
  • Descartes, R., Discourse on Method and The Meditations , translated with an introduction by F. Sutcliffe, Harmondsworth: Penguin, 1968 [Translation of The Meditations by John Veitch, LL.D. available online ].
  • Frege, G., Die Grundlagen der Arithmetik , Bresnau: Koebner, 1884; translated as The Foundations of Arithmetic , J.L. Austin (trans), Oxford: Blackwell, 1974, 2nd rev edition; Original German text available online , (628 KB PDF file), maintained by Alain Blachair, Académie de Nancy-Metz.
  • Gaunilo, “On Behalf of the Fool”, in St. Anselm’s Proslogion , M. Charlesworth (ed.), Oxford: OUP, 1965 [ Available online in the Internet Medieval Sourcebook, Paul Halsall (ed.), Fordham University Center for Medieval Studies, translation by David Burr].
  • Hegel, G., The Ontological Proof According to the Lectures of 1831 , in P. Hodgson (ed.), Lectures on the Philosophy of Religion, Vol. III Berkeley: University of California Press, 1985, pp. 351–8.
  • Hume, D., Dialogues Concerning Natural Religion , 1779, edited with an introduction by H. Aiken, London: Macmillan, 1948.
  • Kant, I., Critique of Pure Reason , 1787, second edition, translated by N. Kemp-Smith, London: Macmillan, 1933.
  • Leibniz, G., New Essay Concerning Human Understanding , 1709, translated by A. Langley, New York: Macmillan, 1896.
  • Spinoza, B., The Ethics , 1677, translation of 1883 by R. Elwes, New York: Dover, 1955 [ Available online , prepared by R. Bombardi, for the Philosophy Web Works project, Middle Tennessee State University].
  • Adams, R., 1971, “The Logical Structure of Anselm’s Argument”, Philosophical Review , 80: 28–54.
  • –––, 1988, “Presumption and the Necessary Existence of God”, Noûs , 22: 19–34.
  • –––, 1995a, Leibniz: Determinist, Theist, Idealist , Oxford: Oxford University Press.
  • –––, 1995b, “Introductory Note to *1970” in K. Gödel Collected Works Volume III: Unpublished essays and lectures , S. Feferman, et al . (eds.), New York: Oxford University Press, pp. 388–402.
  • Alston, W., 1960, “The Ontological Argument Revisited” Philosophical Review , 69: 452–74.
  • Anderson, C., 1990, “Some Emendations on Gödel’s Ontological Proof”, Faith and Philosophy , 7: 291–303.
  • Anscombe, E., 1993, “Russelm or Anselm”, Philosophical Quarterly , 43: 500–4.
  • Antognazza, M., 2018, “Leibniz”, in G. Oppy (ed.), Ontological Arguments , Cambridge: Cambridge University Press, pp. 75–98.
  • Barnes, J., 1972, The Ontological Argument , London: Macmillan.
  • Campbell, R., 1976, From Belief to Understanding , Canberra: ANU Press.
  • Chambers, T., 2000, “On Behalf of the Devil: A Parody of St. Anselm Revisited”, Proceedings of the Aristotelian Society (New Series), 100: 93–113.
  • Chandler, H., 1993, “Some Ontological Arguments”, Faith and Philosophy , 10: 18–32.
  • Charlesworth, M., 1965, Anselm’s Proslogion , Oxford: Oxford University Press.
  • Crocker, S., 1972, “The Ontological Significance of Anselm’s Proslogion ”, Modern Schoolman , 50: 33–56.
  • Diamond, C., 1977, “Riddles and Anselm’s Riddle”, Proceedings of the Aristotelian Society (supplementary volume), 51: 143–68.
  • Dombrowski, D., 2006, Rethinking the Ontological Argument: A Neoclassical Theistic Response , Cambridge: Cambridge University Press.
  • Dummett, M., 1993, “Existence”, in The Seas of Language , Oxford: Oxford University Press.
  • Everitt, N., 2004, The Non-Existence of God , London: Blackwell
  • Ferreira, J., 1983, “Kant’s Postulate: The Possibility or the Existence of God”, Kant Studien , 74: 75–80.
  • Findlay, J., 1949, “Can God’s Existence Be Disproved?”, Mind , 57: 176–83.
  • Garcia, L., 2008, “Ontological Arguments for God’s Existence”, in K. Clark (ed.), Readings in the Philosophy of Religion , Peterborough: Broadview, pp. 16–28.
  • Gorbacz, P., 2012, “PROVER9’s Simplification Explained Away”, Australasian Journal of Philosophy , 90: 585–96.
  • Grey, W., 2000, “Gasking’s Proof”, Analysis , 60: 368–370.
  • Haight, D. and Haight, M., 1974, “An Ontological Argument for the Devil”, Monist , 54: 218–20.
  • Harrelson, K., 2009, The Ontological Argument from Descartes to Hegel , New York: Humanity Books.
  • Hartshorne, C., 1965, Anselm’s Discovery: A Re-Examination of the Ontological Proof for God’s Existence , La Salle, IL: Open Court.
  • Hazen, A., 1999, “On Gödel’s Ontological Proof”, Australasian Journal of Philosophy , 76: 361–377.
  • Henle, P., 1961, “Uses of the Ontological Argument”, Philosophical Review , 70: 102–9.
  • Hinst, P., 2014, “A Logical Analysis of the Main Argument in Chapter 2 of the Proslogion by Anselm of Canterbury”, Philosophiegeschichte Und Logische Analyse , 17: 22–44.
  • Johnston, M., 1992, “Explanation, Response-Dependence, and Judgement-Dependence”, in P. Menzies (ed.), Response-Dependent Concepts , Canberra: ANU/RSSS Working Papers in Philosophy, 123–83.
  • Kovacs, S., 2003, “Some Weakened Gödelian Ontological Systems”, Journal of Philosophical Logic , 32: 565–88.
  • La Croix, R., 1972, Proslogion II and III: A Third Interpretation of Anselm’s Argument , Leiden: Brill.
  • Leftow, B., 2005, “The Ontological Argument”, in The Oxford Handbook of Philosophy of Religion , W. Wainwright (ed.), Oxford: Oxford University Press, pp. 80–115.
  • Lewis, D., 1970, “Anselm and Actuality”, Noûs , 4: 175–88.
  • Lowe, E., 2007, “The Ontological Argument”, in The Routledge Companion to Philosophy of Religion , P. Copan and C. Meister (eds.), London: Routledge.
  • Malcolm, N., 1960, “Anselm’s Ontological Arguments”, Philosophical Review , 69: 41–62.
  • Mann, W., 1972, “The Ontological Presuppositions of the Ontological Argument”, Review of Metaphysics , 26: 260–77.
  • Matthews, G., 2005, “The Ontological Argument”, in The Blackwell Guide to the Philosophy of Religion , W. Mann (ed.), Oxford: Blackwell, pp. 81–102.
  • Matthews, G., and Baker, L., 2010 “The Ontological Argument Simplified”, Analysis , 70: 210–212.
  • Maydole, R., 2009, “The Ontological Argument”, in The Blackwell Companion to Natural Theology , W. Craig and J. Moreland (ed.), Oxford: Blackwell, pp. 553–592.
  • Millican, P., 2004, “The One Fatal Flaw in Anselm’s Argument”, Mind , 113: 437–76.
  • Oppenheimer, P., and Zalta, E., 1991, “On the Logic of the Ontological Argument”, in J. Tomberlin (ed.) Philosophical Perspectives 5: The Philosophy of Religion , Atascadero: Ridgeview, pp. 509–29 [ Preprint available online ].
  • –––, 2011, “A Computationally-Discovered Simplification of the Ontological Argument”, Australasian Journal of Philosophy , 89: 333–349.
  • Oppy, G., 1995, Ontological Arguments and Belief in God , New York: Cambridge University Press.
  • –––, 1996, “Gödelian Ontological Arguments”, Analysis , 56: 226–230.
  • –––, 2000, “Response to Gettings”, Analysis , 60: 363–367.
  • –––, 2006, Arguing about Gods , Cambridge: Cambridge University Press.
  • –––, 2007, “The Ontological Argument” in P. Copan and C. Meister (eds.), Philosophy of Religion: Classic and Contemporary Issues , Oxford: Blackwell.
  • ––– (ed.), 2018, Ontological Arguments , Cambridge: Cambridge University Press.
  • Plantinga, A., 1967, God and Other Minds , Ithaca: Cornell University Press.
  • –––, 1974, The Nature of Necessity , Oxford: Oxford University Press.
  • Priest, G., 2018, “Existence and Necessity”, in G. Oppy (ed.), Ontological Arguments , Cambridge: Cambridge University Press, pp. 250–69.
  • Pruss, A., 2009, “A Gödelian Ontological Argument Improved”, Religious Studies , 45: 347–353.
  • –––, 2010,“The Ontological Argument and the Motivational Centres of Lives”, Religious Studies , 46: 233–249.
  • –––, 2018, “Gödel”, in G. Oppy (ed.), Ontological Arguments , Cambridge: Cambridge University Press, pp. 139–54.
  • Rasmussen, J., 2018, “Plantinga”, in G. Oppy (ed.), Ontological Arguments , Cambridge: Cambridge University Press, pp. 276–94.
  • Redding, P. and Bubbio, P., 2014 “Hegel and the Ontological Argument for the Existence of God”, Religious Studies , 50: 465–86.
  • Rescher, N., 1959, “The Ontological Proof Revisited”, Australasian Journal of Philosophy , 37: 138–48.
  • Ross, J., 1969, Philosophical Theology , New York: Bobbs-Merrill.
  • Rowe, W., 1989, “The Ontological Argument”, in J. Feinberg (ed.), Reason and Responsibility , seventh edition, Belmont, CA: Wadsworth, pp. 8–17.
  • Salmon, N., 1987, “Existence”, in J. Tomberlin (ed.), Philosophical Perspectives 1: Metaphysics , Atascadero, CA: Ridgeview: 49–108.
  • Siegwart, G., 2014, “Gaunilo Parodies Anselm: An Extraordinary Job for the Interpreter”, Philosophiegeschichte Und Logische Analyse , 17: 45–71.
  • Smart, J., 1955, “The Existence of God”, in A. Flew and A. MacIntyre (eds.), New Essays in Philosophical Theology , London: SCM Press: 500–509.
  • Sobel, J., 1987, “Gödel’s Ontological Proof”, in On Being and Saying: Essays for Richard Cartwright , J. Thomson (ed.), Cambridge, MA: MIT Press, pp. 241–61.
  • Sobel, J., 2004, Logic and Theism , New York: Cambridge University Press.
  • Smullyan, R., 1984, 5000 BC and Other Philosophical Fantasies , New York: St. Martins Press.
  • Swietorzecka, K. (ed.), 2012, Gödel’s Ontological Argument: History, Modifications, and Controversies , Portland: Semper.
  • Szatkowski, M. (ed.), 2012, Ontological Proofs Today , Frankfurt: Ontos Verlag.
  • Tooley, M., 1981, “Plantinga’s Defence of the Ontological Argument”, Mind , 90: 422–7.
  • van Inwagen, P., 1977, “Ontological Arguments”, Noûs , 11: 375–395.
  • Wilson, M., 1978, “Immutable Natures and the Ontological Argument”, in Descartes London: Routledge, 172–6.
  • Zagzebski, L., 1984, “Oakes’s New Modal Argument for the Existence of God”, International Journal for Philosophy of Religion , 20: 159–64.
How to cite this entry . Preview the PDF version of this entry at the Friends of the SEP Society . Look up topics and thinkers related to this entry at the Internet Philosophy Ontology Project (InPhO). Enhanced bibliography for this entry at PhilPapers , with links to its database.
  • Medieval Sourcebook: Philosophers’ Criticisms of Anslem’s Ontological Argument for the Being of God (Paul Halsell, Fordham University)
  • Ontological Argument Revisited by Two Ottoman Muslim Scholars (Umit Dericioglu)
  • The Ontological Argument (Kenneth Himma, University of Washington)
  • Hegel and Kant on the Ontological Argument (Maria de Lourdes Borges, Federal University of Santa Catarina)
  • Ontological Argument (links to papers on ontological arguments)
  • “ Formalization, Mechanization and Automation of Gödel’s Proof of God’s Existence ”, unpublished manuscript.
  • “ Automating Gödel’s Ontological Proof of God’s Existence with Higher-order Automated Theorem Provers ”, published in ECAI 2014, T. Schaub et al . (eds.), IOS Press.

Anselm of Canterbury [Anselm of Bec] | a priori justification and knowledge | Descartes, René | existence | God: and other ultimates | Gödel, Kurt | Hegel, Georg Wilhelm Friedrich | Kant, Immanuel | logic: informal | logic: modal | Meinong, Alexius

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Essay – Ontological Argument

September 15, 2020.

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“It is impossible to argue for the existence of God from his attributes”. Discuss

This essay was submitted by one of my students. At first glance, the ontological argument seems a bit odd: is it really possible to argue God exists by just using defintiions and philosophical ideas? But perhaps Anselm is not trying to prove God exists, more giving grounds for havingthe id ea of a supreme being as something great, profound and on the edge of human understanding. I give my comments as the essay progresses. PB

Arguably, we cannot derive the existence of God from His definition due to the inherently ambiguities of the predicate, existence, and indeed the nature of the subject Himself, God. Beyond this, the definition that would be used – a supremely perfect being – deeply undermines the theological idea of an epistemological space (extolled by John Hick), which allows us to develop a more meaningful relationship with God based on faith.

Excellent opening paragraph which brings in the idea of epistemic distance, introduced by John Hick, and hits at an attack on Anselm’s first premise, that God is that which nothing greater can be conceived.

This type of argument, an ‘ontological argument’ is  a priori, and deductive. Medieval Platonic Monk Anselm produced one, which tries to show that God is ‘de dicto necessary’ (i.e. necessary through language). It begins with Anselm, who argues (in his ‘Prosologion’) that God is ‘that – thus – which – nothing – greater – can – be – conceived’. He makes the case that if we were to compare a log to a horse they might say that the horse is greater (i.e. having movement). Likewise, if they were to compare a horse to a human, they might conclude that the human is greater (i.e. having faculties of reason). Therefore, there must be some ‘supreme good’ which allows these comparisons to be drawn, and from which other matter confers value. This, he knows to be God (akin to Plato’s ‘Form of the Good’).

Again, a good paragraph, which is really discussing the issue of placing a comparison (greater than) at the heart of the first discussion in Prosologion. 

From this definition in Anselm’s ‘Proslogion’, he argues that things can either exist in the mind (in re)/continually or in the mind AND reality (in re & in intellect)/necessarily. And, as God is that – thus – which – nothing – greater – can – be – conceived, He must therefore exist both in the mind AND in reality, for this must be better than to exist in the mind alone (and God is a supremely perfect being. In other words, by virtue of the way we define God, Anselm believes His existence to be necessary; alluding to Psalm 14 (the fool says in his heart, “there is no God”).

Yes, and of course, the idea of the necessary being is something Anselm discusses further in the second version of his ontological argument. Sometimes this is expressed in terms of an a analogy with a triangle. A triangle necessarily has three sides, whereas many attributes (predicates as Kant calls them) of a thing are just contingent (ie grass is only contingently green because if there’s a draught it is actually brown).  Anselm’s argument is that only God has certain qualities by necessity (and so in the end the Gaunilo analogy of the island, see next paragraph, is a false analogy, says Anselm).

A contemporary of Anselm, Gaunilo, responds by writing (his ‘On behalf of the fool’) that this allows anything to be ‘thought into existence’. He imagines a perfect ‘lost island’, with warm seas, white sandy beaches and so on. This island could either exist in the mind, or in the mind AND reality. Since it’s better to exist in the mind AND reality, this island must therefore exist in reality (i.e. being perfect). Clearly, as this island doesn’t exist, the argument falls short for God too (a ‘reductio ad absurdum’). However, this is one of the weaker criticisms of the Ontological argument, as it doesn’t make sense to think of islands necessarily. They are, by definition, dynamic landforms which shift and come into or go out of existence over millions of years. That is, they are wholly contingent.

Exactly Anselm’s point and beautifully expressed here.

As aforementioned, the greatest drawback of this type of argument is its assumption that existence is a predicate at all. As an existent God appears not to add anything to our understanding of Him. A well-educated Theologian and a well-educated atheist have exactly the same conceptions of God, even if there’s disagreement over His existence.

Again this is an excellent point as an atheist would simply reply to Anselm that God necessarily does not exist.

This was the argument set out most notably by German Philosopher Kant, in response to a reformulation of the Ontological argument by Descartes (in brief, that a supremely perfect being must have the ‘perfection’ of existence’). Beyond existence appearing not to be a predicate, there’s arguably no reason why we cannot believe that if such a supremely perfect being existed, He would have existence. (But, since He doesn’t, He does not). For example, one can describe the perfect mermaid as being half-human, half-fish and as having existence, whilst still rejecting the concept of a perfect mermaid in its entirety. Therefore, the problems with understanding both the nature of existence and the essence of God mean that we cannot derive the existence of God from His definition, Anselm argues, that things can either be self-evidently true in themselves, or self-evidently true in themselves and to us. Although, for them to be self-evidently true in themselves and to us, we must have complete understanding of existence and God (i.e. the predicate and the subject), which we do not. As such, one can make the case that God’s definition makes His existence self-evidently true in itself but this form or argument (from definition) does not convincingly show that God’s existence is self-evidently true to us.

Very good paragraph, clearly argued and correctly linking Kant to Descartes, whose version of the ontological argument is not quite as subtle as Anselm’s. It is a good point to stress that something defined as self-evidently true is not the same as something established as self-evidently true. And the whole basis of the argument is rejected by thinkers like Aquinas who felt that God is beyond understanding and so applying such logical and linguistic categories was misplaced.

Finally, many theologians write about a ‘self-limitation’ of God’s divine attributes, in order for Him to allow us a more genuine relationship to develop. In other words if God’s existence was completely known to us by definition, we would have no choice as to whether to believe in Him or not. What makes a relationship with God valuable is the fact that we freely choose to believe in it through faith. 1 Corinthians (i.e. St Paul) refers to this ambiguity when it is written that we ‘see God through a glass, darkly’. There is scant Biblical evidence to the contrary, that God’s definition is completely known to us. Theologian John Hick refers to this as our epistemological space’ (or ‘knowledge gap’) in which to operate.

Yes, sometimes referred to as ‘epistemic distance”.

To conclude, we certainly cannot derive God’s existence from His definition due to the problematic logic, with which He is referred and because taking this to be true would critically undermine our freedom to engage in a relationship with Him. Or, as DZ Phillips suggests, perhaps it doesn’t make sense to question God’s existence at all. Instead, we shall take this as the starting point for theology, in the same way that other academic subjects of integrity have axioms on which further investigation rests (e.g. Maths, Physics, Chemistry).

Excellent essay, very clearly and throughly argued. The student might have referred to some modern thinkers such as Alvin Plantinga who has sought to rehabilitate the ontological argument by defining  God as ‘maximally excellent’, or Norman Malcolm, who argues that that Kant’s criticism of the argument is quite misleading, since the question is not whether existence is a predicate but whether necessary existence is a predicate (1960). Reference might have been made to Anselm’s second version because this embraces the idea of necessary existence being an attribute of God’s perfection.

Total 37/40 A* 

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1000-Word Philosophy: An Introductory Anthology

1000-Word Philosophy: An Introductory Anthology

Philosophy, One Thousand Words at a Time

The Ontological Argument for the Existence of God

Author: Andrew Chapman Category: Philosophy of Religion Word Count: 1000

1. God’s Greatness

The Abrahamic conception of God is that he’s awesome —all-powerful, all-knowing, all-good, creator of the universe, self-existent, and a host of other properties that make him not just very, very great, but the greatest that there is or could possibly be.

“This is all fine and good,” say non-theists, “but this is a description of a being whose existence we don’t affirm.” However, a famous and powerful argument for God’s existence known as the Ontological Argument purports to be able to show that God’s being the greatest possible being entails God’s existence: the mere definition of God proves his existence.

This essay introduces this argument. 

Anselm

2. Anselm’s Ontological Argument

There are different versions of the Ontological Argument, but we will focus on one of the earliest, set forth by St. Anselm (1033-1109). 1

As we’ve already noted, God is the being than which no greater can be conceived . This is Anselm’s somewhat unwieldy description of God, which we can abbreviate as BNGC . By definition, BNGC is the greatest conceivable being. If you think you’re conceiving of God and you can possibly conceive of a greater being, then you weren’t initially conceiving of God. Simple enough.

Now, certainly you can conceive of God. To conceive of something is just to think about it clearly and distinctly; you’ve been doing that since the beginning of this essay. So we know, at least, that God can exist in conception , i.e., can be conceived. Even atheists admit this. What the atheist is denying, and what the agnostic is refusing to affirm or deny, is that God exists in reality . So we have an intuitive distinction between a thing that exists merely in conception and a thing that exists in reality as well as in conception .

Now here’s the argument: Assume that the atheist is right, that God doesn’t exist in reality, but merely in conception. But then there would be another possible being, a God who exists not merely in conception but also in reality as well, who is greater than BNGC. 2 That is, there would be a possible being who is greater than the being than which no greater can be conceived. But no being can be greater than the being than which no greater can be conceived—that’s a flat-out contradiction! So our original assumption, that God doesn’t exist in reality, but merely in conception, must be false, since any assumption that entails a contradiction must be false. Therefore, God must exist both in conception and in reality. Therefore: God exists. 3

The Ontological Argument is remarkable in that it reasons from premises containing only definitions and logical laws to perhaps the grandest philosophical conclusion there is. We can know that God exists merely by reflecting on the concept of God .

Many people, however, have been uncomfortable with the purported fact that we can prove the Almighty’s existence so apparently simply. Numerous critics, theist and non- alike, have criticized different aspects of the Ontological Argument. Let’s look at just two of the most influential criticisms: those provided by Gaunilo of Marmoutiers (994-1083) and Immanuel Kant (1724-1804).

3. Gaunilo’s Criticism

Gaunilo was a monk and a contemporary of Anselm’s. In his “Reply on Behalf of the Fool,” 4 Gaunilo has us imagine another really awesome thing: the island than which no greater can be conceived —let’s call it INGC . This island has all the amazing-making properties you can think of: pristine white-sand beaches for lounging, warm water for swimming, and not a tourist in sight. But certainly such an island’s existing only in conception would entail a contradiction, since then there would be a possible thing greater than the INGC, namely, the existing INGC. Therefore, the INGC exists. And, of course, since we have picked island arbitrarily, we can run the same argument for any object: a building, a mousetrap, a horse, whatever you please. 5

What Gaunilo has shown, then, is that, using Anselm’s form of reasoning , we can prove the existence of all sorts of bizarre entities, entities that clearly don’t exist. Accordingly, concludes Gaunilo, there must be something fatally wrong with Anselm’s reasoning. 6

4. Kant’s Criticism

Which do you prefer, coffee or existing coffee ? Notice that this is different from the question of whether you prefer coffee or no coffee at all . No coffee isn’t coffee while both coffee and existing coffee are coffee just the same! If it seems like we’re verging on Lewis Carroll-style nonsense here, you’re right, and this is exactly Kant’s criticism of the Ontological Argument.

According to Kant in his Critique of Pure Reason , what’s gone wrong with Anselm’s argument lies in the distinction between a thing that exists merely in conception and a thing that exists in reality as well as in conception . According to Anselm, there are two different sorts of things : those that exist merely in conception and those that exist in reality as well as in conception. But an existing thing and its non-existing counterpart aren’t two different sorts of thing —one merely exists and the other doesn’t. While it is certainly true that some things exist and others do not, existing does not make a thing a different kind of thing from its non-existing colleague.

The upshot of this, says Kant, is that existence is a very special type of property, one not suited for the type of argument Anselm is running. Since there is no difference between the group of objects falling into the class God and those falling into the class existing God , an existing God can be no better and no worse than a mere God. There’s simply no relevant difference in kind between a God who exists and a God who doesn’t.

5. Conclusion

Of course, Gaunilo and Kant have not had the last word in this debate. Powerful arguments have been mounted in response to Gaunilo’s and Kant’s criticisms of the Ontological Argument. Additionally, increasingly complex versions of the Ontological Argument have been developed and debated. One thing that’s certain is that the Ontological Argument, whether sound or unsound, is a fascinating and powerful attempt at a proof for the existence of God.

1  Two other famous formulations of the argument are Descartes’s formulation from the conception of existence as a perfection  (see  Descartes’ Meditations 4-6 by Marc Bobro) and Alvin Plantinga’s so-called Modal Ontological Argument (see Modal Ontological Arguments for the Existence of God by Thomas Metcalf). 

2  Which is greater, a God who exists merely in conception or a God who exists in reality as well as in conception? Think of all the things a God who exists in reality as well as in conception can do that a God who exists merely in conception cannot do: He can create worlds. He can listen to prayers. He can be the ultimate source and ideal form of goodness. He can reward virtuousness and punish vice… Those all seem like great things, and a God who exists merely in conception can do none of them.

3  You may remember this type of argument or proof from your geometry courses where it was called an indirect proof . Philosophers and logicians call this a reductio ad absurdum , or a reduction to absurdity. The strategy, as you have seen, is to assume the opposite of what you are trying to prove, show how that assumption entails either a contradiction or some other form of absurdity, and then to reject the original assumption.

4  “The fool has said in his heart, ‘There is no God.’” (Psalm 14:1)

5  It’s important to note that we’re not merely talking here about the greatest actually existing island, mousetrap, horse…, but the greatest possible island, mousetrap, horse… It is plausible that for any type of existing object, one of the ones that exists is the best one (in terms of whatever makes that sort of thing a good one of what it is). But it is another thing altogether to talk about the greatest possible or greatest conceivable such object.

6  Notice that Gaunilo’s argument is also a reductio ad absurdum:  Assume that Anselm’s reasoning is valid and an absurdity results. Therefore, Anselm’s reasoning must be flawed.

Anselm, St.,  Proslogion , in  St. Anselm’s Proslogion , M. Charlesworth (ed.), Oxford: OUP, 1965.

Descartes, R., Discourse on Method and The Meditations , translated with an introduction by F. Sutcliffe, Harmondsworth: Penguin, 1968.

Gaunilo, “On Behalf of the Fool”, in St. Anselm’s Proslogion, M. Charlesworth (ed.), Oxford: OUP, 1965.

Kant, Immanuel.  Critique of Pure Reason . Trans. Paul Guyer and Allen W. Wood. Cambridge: Cambridge UP, 1998.

Oppy, Graham. “Ontological Arguments.”  Stanford Encyclopedia of Philosophy . Stanford University, 08 Feb. 1996. Web. 27 June 2014.  

Related Essays

The Concept of God: Divine Attributes  by Bailie Peterson

Descartes’ Meditations 4-6  by Marc Bobro

Modal Ontological Arguments for the Existence of God by Thomas Metcalf 

Possibility and Necessity: An Introduction to Modality  by Andre Leo Rusavuk

Modal Epistemology: Knowledge of Possibility & Necessity  by Bob Fischer

About the Author

Andrew Chapman is a lecturer in philosophy at the University of Colorado, Boulder. He holds a PhD in philosophy from the University of Colorado, Boulder, an MA in philosophy from Northern Illinois University and a BA in philosophy and a BM in bassoon and sound recording technology from Ithaca College. He specializes in epistemology, metaethics, and the history of philosophy (especially Kant and the 20th Century Anglophone and Phenomenological traditions). When not philosophizing, Andrew is skiing, hiking, listening to great music, or playing the bassoon. www.colorado.edu/philosophy/people/andrew-d-chapman  

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Graham Oppy, editor: Ontological arguments

Cambridge University Press, Cambridge, 2018, x and 284 pp, $34.99 (paper)

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  • Published: 27 June 2019
  • Volume 86 , pages 91–96, ( 2019 )

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The Many - Faced Argument (ed. Hick and McGill, Macmillan 1967). A very large volume, edited by Miroslaw Szatkowski, appeared in 2013 ( Ontological Proofs Today, Ontos Verlag). That includes much advanced work, but is expensive and much less accessible than the volume under review.

See especially p. 57.

“The Ontological Argument as Cartesian Therapy,” Canadian Journal of Philosophy 35(4), pp. 521–562.

“Ontological Arguments” in Stanford Encyclopedia of Philosophy ; https://plato.stanford.edu/entries/ontological-arguments/ , accessed May 22, 2019.

Lewis, David, "Anselm and Actuality," Nous volume 4, number 2 (1970), pp. 175–188.

The Nature of Necessity (Oxford: Oxford University Press, 1974), p. 221.

See his “Three Versions of the Ontological Argument” in Ontological Proofs Today, Miroslaw Szatkowski (editor), Ontos Verlag 2012, pp. 143–162.

NB: Descartes gives such a restriction, but this involves “clear and distinct perception” by the meditator.

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The argument that a necessarily perfect dog must exist works in three steps each of which can be understood to possess particular presuppositions. To begin with, the argument presupposes “perfection” as something that may be divided into a variety of conceivable predicates and that each of these predicate may be then be assigned to a being that is deemed to be entirely perfect. Importantly, these perfections require the “idea” of a perfect dog. Fido, in this argument, is a perfect instantiation of a the idea of a dog, and it is only against this idea that his perfection can be measured. Fido is not perfect in every singe way, rather he is simply perfect in terms of his “dogness.”

If one understands that existence is a predicate of a being, then it must necessarily be the case that a being that possesses all possible perfections must necessarily exist. If a perfect dog did not exist then it would be less than perfect; leading to a contradiction within the first of the argument. From this perspective, it seems that argument is sound, and rationally correct. However, there are two immediate responses which can be given to it. The first of these it is an essentially idealist argument. Without the conception of the actually existing universal dog, of which Fido is the most perfect instantiation then the argument, and the very idea of perfection that it employs If one denies the active existence of such universals and adopts a nominalist stand point, then the argument ceases to hold any weight. Not only does the idea of perfection disappear, but so does the conception that such perfection can be understood as an accumulation of particular predicates; amongst which may be included existence.

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It is clear that this argument has clear relevance for more conventional ontological arguments. According to Joel Friedman (1979), for an argument to qualify as an ontological argument then it “must start with some definition of God, as a premise, and together with additional a priori premises, finish with the existence of God, as a conclusion” (p. 73). That is, an ontological argument seeks to prove to the existence of God from its definition, and without any reference to material being. By starting from the definition of God as a being that is absolutely perfect; that is that possesses all possible predicates to the highest level of intensity and efficacy, the argument then seeks to prove that a contradiction ensues if this being does not exist, and it can therefore be argued to provide a variation on the ontological argument concerning Fido. It takes the supreme idea of a supreme being, and, by defining such a being as perfect, seeks to prove that it must exist in reality.

Crucial to Kant’s criticism of this argument is the suggestion that it represents an essentially analytic truth; i.e. its conclusion is contained within its definition and, therefore, it does not concern the actual positive existence of God, but rather the logical structure of the idea of him. Kant writes, therefore, that “that the conditioned necessity of judgements…is not an absolute necessity of things” (1998, p. 564). Necessity understood as emerging from an analytic truth can only be understood to form a precondition for the possible existence of something, it cannot prove its actual existence. That is to say that, according to Kant, the ontological argument can be understood to be stating that “if God exists, he must necessarily exist” but that this is essentially a tautology and cannot provide an understanding of God outside of our own idea of him. As such, Kant’s essential point about the ontological argument itself is that it highlights a particular truth about a mode of thinking, but that this cannot be translated into an argument for the positive existence of God.

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46 Ontological Argument Essay Topic Ideas & Examples

🏆 best ontological argument topic ideas & essay examples, 📌 good research topics about ontological argument, 🔎 interesting topics to write about ontological argument.

  • Ontological Arguments: Anselm’s Ontological Argument For example, Descartes notion of existence of a perfectly supreme being is questionable because, unless one proves that the reality of the Supreme Being is coherent, then the argument is void. Anselm’s argument that God […]
  • The Ontological Argument to Prove God’s Existence According to Anselm “if the existence of a being is necessary, then, ‘that being is greater than one which existence is not necessary’”. We will write a custom essay specifically for you by our professional experts 808 writers online Learn More
  • Ontological and Wager Argument While Anselm and Wager are major proponents of the ontological argument, Hume and Kant are some of the opponents of the ontological argument. Ontological argument is a controversial argument that supports the existence of God.
  • The Ontological Argument for the Existence of God Kant’s objection to the ontological argument stems from his view of the concept that a being that is conceived in the human mind, and which exists in the real world, is superior to an idea […]
  • Philosophy: St. Anselm’s Ontological Argument One of the earliest ontological arguments, in defense of the de facto existence of God, is that of Anselm of Canterbury.
  • Anselm: Ontological Argument for the God’s Existence He considers the understanding of God’s existence as some of the things that exist in the stated place. He states that the love for God is the main aspect of the just among the human […]
  • Descartes’ Ontological Argument and Zhuangzi’s Arguments Against Realism
  • What Are the Strengths of the Ontological Argument for God’s Existence?
  • Comparison and Contrast of the Cosmological and Ontological Arguments
  • Ontological Relativism and the Pragmatic Notion of Metaphysical Truth
  • Ecological Psychology and Enactivism: A Normative Way Out From Ontological Dilemmas
  • Transcending Ontological Uncertainty With Nietzsche’s Will to Power
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  • Happiness Revisited: Ontological Well-Being as a Theory-Based Construct of Subjective Well-Being
  • Descartes Ontological Argument for God’s Existence
  • The Three Main Points of the Ontological Argument
  • Liberalism and Capitalism: Contradictory Ethical and Ontological Landscapes
  • Explaining the Ontological and Epistemological Assumptions
  • Descartes’ Meditations: Ontological Argument
  • Philosophy: Ontology and God’s Right Hand
  • Ontological Pluralism: The Solution to Limited Racial Problematization
  • Anselm’s Ontological Argument and Gaunilo’s Response
  • St. Anselm’s Ontological Argument from Philosophical Perspectives
  • Disputing the Modal Ontological Argument: The Evil-God Objection
  • Ontological Argument and Pascal’s Wager
  • Leadership and the Development of Effective Ontological and Epistemological Frameworks
  • Key Concepts of the Ontological Argument for the Existence of God
  • The Explanatory Logic and Ontological Commitments of Generalized Darwinism
  • Outlining the Ontological Arguments and Their Success as Proofs of God’s Existence
  • Hume, Kant, and Descartes’ Teleological, Ontological, and Cosmological Arguments and God’s Existence Criticisms
  • Ontological and Cosmological Arguments for God’s Existence
  • Does the Ontological Argument Successfully Show That God Exists?
  • Epistemological Problems and Ontological Solutions: A Critical Realist Retrospective on Althusser
  • Relationship Between Ontology, Epistemology, and Methodology
  • The Ontological Argument Presented by Descartes and the Cosmological Argument Presented by Aquinas
  • Cosmological, Ontological, and Teleological Arguments – Evidence in Proving Existence of the Supreme Personal Being
  • The Ontological Argument: Arguments for and Against Faith and Religion
  • Debating Anselm’s Ontological Argument: From Kant to Contemporary Scholars
  • Ontological Argument: Two-Dimensional Version
  • The Casual and Ontological Argument of God’s Existence
  • Ontological Argument From Anselm and Gaunilo’s Objections to It
  • Religion, Faith, and the Ontological Argument
  • God’s Existence and the Ontological Argument
  • Ontological Discussion After Anselm’s Viewpoint
  • Axiological, Ontological, and Epistemological Arguments Featured in the ‘Republic’ by Plato
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  1. Ontological Arguments

    Ontological arguments are arguments, for the conclusion that God exists, from premises which are supposed to derive from some source other than observation of the world—e.g., from reason alone.

  2. Ontological argument

    An ontological argument is a philosophical argument, made from an ontological basis, that is advanced in support of the existence of God. Such arguments tend to refer to the state of being or existing.

  3. Anselm: Ontological Argument for God's

    1. Introduction: The Non-Empirical Nature of the Ontological Arguments It is worth reflecting for a moment on what a remarkable (and beautiful!) undertaking it is to deduce God's existence from the very definition of God. Normally, existential claims don't follow from conceptual claims.

  4. Essay

    September 15, 2020 "It is impossible to argue for the existence of God from his attributes". Discuss This essay was submitted by one of my students. At first glance, the ontological argument seems a bit odd: is it really possible to argue God exists by just using defintiions and philosophical ideas?

  5. The Ontological Argument for the Existence of God

    Anselm's Ontological Argument There are different versions of the Ontological Argument, but we will focus on one of the earliest, set forth by St. Anselm (1033-1109).1 As we've already noted, God is the being than which no greater can be conceived. This is Anselm's somewhat unwieldy description of God, which we can abbreviate as BNGC.

  6. Ontological Argument (Overview)

    An ontological argument is a philosophical argument for the existence of God that uses ontology. Many arguments fall under the category of the ontological, and they tend to involve arguments about the state of being or existing. More specifically, ontological arguments tend to start with an a priori theory about the organization of the universe. If that organizational structure is true, the ...

  7. Graham Oppy, editor: Ontological arguments

    It is a welcome development, since there has not been a similarly accessible collection of essays on ontological arguments since 1967. 1 The volume will serve as an excellent text for advanced courses on philosophical theology or seminars on ontological arguments, and even as a supplementary text for surveys of philosophy of religion.

  8. The Ontological Argument and the Ensuing Arguments About it

    This essay provides an introduction to the ontological argument, specifically examining the version put forth by St. Anselm, the reply by Gaunilo and Anselm's rejoinder, early modern developments such as Descartes' ontological argument, later modern arguments such as Kant's criticism of existence as a predicate, and contemporary variants of the ...

  9. Ontological argument

    ontological argument, Argument that proceeds from the idea of God to the reality of God.It was first clearly formulated by St. Anselm in his Proslogion (1077-78); a later famous version is given by René Descartes.Anselm began with the concept of God as that than which nothing greater can be conceived. To think of such a being as existing only in thought and not also in reality involves a ...

  10. PDF The Ontological Proof: Kant's Objections, Plantinga's Reply

    tructive critique of the ontological argument ever produced. 2 The aims of this essay are, first, to present Kant's cr iticism of the ontological argument (or better, arguments 3—herein I use 1 I am grateful to Gary Banham, Andrew Janiak, and two anonymous reviewers at Kant Studies Online for their feedback on earlier versions of this paper.

  11. Strengths and Weaknesses of The Ontological Argument

    Strengths of the Ontological Argument The main strength of Anselm's argument is showing that the concept of God is not illogical, though explaining that everyone, even a non-believer must have a concept of God in the mind and because of this have a concept of God existing in reality.

  12. ontological argument essay

    The Ontological argument is an a priori argument that seeks to prove the existence of God on the grounds of reason. The two classical formulations of the argument were put forward by 11th century Bishop Anselm and the 17th century French mathematician and philosopher Rene Descartes.

  13. The Ontological Argument for the Existence of God Essay

    The ontological argument is an a priori argument that attempts to prove God's existence based purely on reason. The argument sees no reason for attempts to prove the existence of God using empirical approaches. Instead, it seeks to prove God's existence using essence.

  14. Philosophy: St. Anselm's Ontological Argument

    One of the earliest ontological arguments, in defense of the de facto existence of God, is that of Anselm of Canterbury (St. Anselm). As of today, it is being often referred to as such that contributed rather substantially towards the theological legitimization of Christianity during the Dark Ages.

  15. Graham Oppy, editor: Ontological arguments

    collection of essays on ontological arguments since 1967.1 The volume will serve as an excellent text for advanced courses on philosophical theology or seminars on ontological arguments, and even as a supplementary text for surveys of philosophy of religion. Otherwise it makes a nice addition to the student library.

  16. The Ontological Argument For God's Existence

    Part 1: Apologetics for Everyone Part 2: The Cosmological Arguments. P rofessional philosophers commonly regard the Ontological Argument as the best single logical argument in favor of God's existence. In fact, many secular philosophers have conceded that the Modal Ontological Argument (the version of the argument under consideration in this article) holds up under even the most rigorous ...

  17. 81 Ontology Essay Topic Ideas & Examples

    Ontology as a name was developed from a Greek word 'onto' which means 'being' or 'that which is.'. Ontology is a branch of metaphysics that deals with issues about the existence of entities, and how […] While Anselm and Wager are major proponents of the ontological argument, Hume and Kant are some of the opponents of the ...

  18. Can Anselm Ontological Argument Prove the Existence of God

    Before I begin my argument I will reconstruct the a priori ontological argument put forward by Anselm to prove the existence of the Greatest Conceivable. Anselm begins his argument by introducing "the fool", a reference to Psalms 53:1. This fool "has said that in his heart, [that] there is no God", or denying the existence of God ...

  19. Essay on The Ontological Argument for the Existence of God

    The ontological argument argues that if you understand what it means to talk about God, you will see His existence is necessarily true. Anselm defined God as 'that than which nothing greater can be conceived', hence God must exist. Anselm also believed that even …show more content…

  20. Analysis Of The Ontological Argument Philosophy Essay

    The father of Ontological arguments is often considered to be Anselm of Canterbury who was a monk and abbot of Bec in Normandy, and Archbishop of Canterbury from 1093 to 1109. Anselm when discussing topics with his pupils mainly focused on the nature and the existence of God. Throughout history there have been many disagreements over whether ...

  21. The Ontological Argument

    The Ontological Argument. The argument that a necessarily perfect dog must exist works in three steps each of which can be understood to possess particular presuppositions. To begin with, the argument presupposes "perfection" as something that may be divided into a variety of conceivable predicates and that each of these predicate may be ...

  22. 46 Ontological Argument Essay Topic Ideas & Examples

    Table of Contents 🏆 Best Ontological Argument Topic Ideas & Essay Examples Ontological Arguments: Anselm's Ontological Argument For example, Descartes notion of existence of a perfectly supreme being is questionable because, unless one proves that the reality of the Supreme Being is coherent, then the argument is void.