Tuesday, April 23, 2013

Kant's Criticism of the Ontological Argument

One of the most famous (and supposedly devastating) criticisms of Anselm’s ontological argument comes from Immanuel Kant. It is virtually undisputed by those who mention the argument. One hears this criticism even on the Internet. In nearly every instance in which I have encountered this objection, an explanation is never provided. What is this criticism, and what does it mean? 

Kant claimed that “existence is not a predicate.” To illustrate what this means, consider an apple (or a horse, or a pencil, or any other object). One may describe it as “red,” and “sweet,” and any number of things. All of these are in the predicate position in a sentence. They translate into properties of the object like being red or being sweet. Kant held that in order for something to count as a property, it had to tell us something about the object that added to its description. Kant’s argument is that two apples will be identical where they have all of the same properties, even if we stipulate that one of them exists. If that is correct, then existence is not a property after all. But if existence is not a property, then Anselm cannot be correct when he says it is greater for God to exist in reality than merely in the intellect (since the difference between the two would be only in existence). So, is Kant right?

It seems that there is good reason to doubt that he was. First, Stephen T. Davis points out that actually-existing things do have properties, by virtue of their existence (although they are accidental ones), that they would not have were they not to exist.[1] For example, the concept of a hundred dollars does not possess the accidental property of having purchasing power in the real world. [2] So, there are, or at least can be, relevant differences between identical concepts brought about by existence. Therefore, existence does, in at least some cases, add something to a concept.

Second, Davis gives an example of the perfect chancellor. [3] The idea can be extrapolated to the perfect person, or ruler, or whatnot. Take two conceptual persons who embody this perfect X. Suppose one person, A, satisfies all of the criteria for being a perfect X. However, A is a fictional character in a story. B has an identical list of attributes, but as it turns out, lives in northwestern Montana. What sense does it make to say there is no difference between fictional A and actually-existing B? But then it follows existence can be a real property or predicate.

“But wait!” I hear an objector say. “That doesn’t show that the concept of God is such a concept that allows for the predication of existence!” Perhaps, perhaps not. However, at the very least, it has been shown that existence can function in some instances as a predicate, so that doubt upon Kant’s criticism has been cast. It will no longer do merely to quote Kant. One will have to show that the concept of God is such that existence cannot be properly predicated of it.

Many have abandoned Anselm’s formulation of the argument for this criticism. I do not see the need to do so. While there are other ontological arguments I prefer (such as Plantinga’s modal ontological argument), Kant’s criticism does not damage Anselm’s nearly as much as many think.

1 Stephen T. Davis, God, Reason, and Theistic Proofs (Grand Rapids, MI: Eerdmans Publishing, 1997), 35.

2 It just does not matter that the conceptual hundred dollars has the counterfactual property of having purchasing power in the real world, where we would say “If this hundred dollars were actual, then it would possess the property of having purchasing power in the real world.” This is because, whatever the grounding for counterfactual properties, it nonetheless remains that the concept does not, in fact, possess this actual property.

3 Davis, 35.


  1. Randy, wouldn't Aquinas' distinction between essence and existence support the notion that existence is a property?

    If we were to say that in addition to being a bird that burns to ashes, out of which another arises, a Phoenix also exists, surely that'd being adding to the description.


  2. Hello Frank! As I understand Aquinas, and divine simplicity, there just would be no difference between God's essence and existence, so that they are one and the same (at least as far as entailments are concerned, anyway). But I agree with the metaphor; existence is surely adding to the description of the object.

  3. Heyllo Randy J

    Perhaps you’d be so kind as to comment on a criticism that’s been leveled against the notion that existence is a property.

    “…it is necessary first to briefly summarize a notion of existence first introduced into modern logic by Gottlob Frege. Take a sentence like “cats exist.” At first glance this seems to predicate existence of a certain kind of object, namely cats. But Frege argued that this appearance is misleading. Existence, he claimed. Is not a predicate f objects (that is to say, a first level predicate),but rather a predicate of concepts ()that is to say, a second level predicate). In this case, it is being predicated of the concept ‘being a cat’. Hence, to reveal the logical structure of the sentence in question, we’d have to rewrite as saying something like “There is at least on x such that x is a cat.” This does not tell us that a certain object has the property of existence; rather it tells us that there is at least one thing falling under a certain concept. Thus, the sentence in question does not tell us something about individual cats, but rather about the concept of being a cat.

    A standard argument for the view that this Fregean notion of existence is the only legitimate notion is that if existence were a first level predicate of objects, then (it is claimed) negative existential statements like “Martians do not exist” would be self contradictory, which they obviously are not. For if we think of this statement as saying tat Martians do not have the property pf existence, this would seem to entail that there are (I.e. there exist) certain creatures, namely Martians, who lack existence. Since that is absurd, the statement “Martians do not exist” cannot be interpreted as denying a property or attribute of existence to some object or objects. It should rather be interpreted in light of Frege’s doctrine of existence as saying something like “It is not the case that there is at least one x such that x is a Martian.” That is to say, it says o the concept ‘being a Martian’ that there is nothing to which it applies.”

    I apologize if this is off topic. Hope all is well with you.

    God bless, Frank

    1. Hello Frank, as I understand it, Frege is trying to be precise, so that we can avoid committing ourselves to whatever it is of which we speak. That's why he would say "Martians do not exist" seems incoherent (that is, it would be like saying "There exist Martians, but the existing Martians do not exist"). I think it's important to understand that Frege's considerations more resemble philosophy of language than they do ontological properties. But surely even here, an actually-existing Martian adds to a concept, and thus distinguishes it. One criticism I would have of this kind of discussion is, according to what is written above, there would be no difference in properties between two identical Xs, X1 and X2, where X1 is fictional and X2 is not. But surely that is false, for we can say of X2, "X2 exists," whereas we cannot say that of X1.

      One last, brief comment. It may help to distinguish between types of existence, as Anselm does. This way, we can say, "Martians do not exist" and not thereby commit ourselves to existing non-existent Martians. When we mean "exist" for "Martians," we mean so conceptually. When we use "exist" for the negation, we mean that in the actually-existing sense. This distinction renders an incoherence charge as moot, for we just aren't using "exist" univocally.

  4. Makes perfect sense. Thanks a bunch Randy :)


  5. As far as I understand, Kant was criticizing Descartes' and Leibniz's formulation of the argument, NOT Anselm's. They do use existence as a property. But Anselm does not. One formulation of his argument includes the three premises:

    1. The Greatest Conceivable Being exists as a concept but not as reality (premise for reductio)
    2. Existence as both a concept and in reality is greater than existence as a concept alone
    3. It is conceivable that the GCB exists as both a concept and in reality

    Note at no point does he use existence as a property. Plantinga says:

    "If this is what [Kant] means, he's certainly right. But is it relevant to the ontological argument? Couldn't Anselm thank Kant for this interesting point and proceed merrily on his way? Where did he try to define God into being by adding existence to a list of properties that defined some concept?...If this were Anselm's procedure -- if he had simply added existence to a concept that has application contingently if at all -- then indeed his argument would be subject to the Kantian criticism. But he didn't, and it isn't."

    1. Very helpful, Martin. I very much appreciate the comment (and the passage reads as very familiar to me, which means I've probably read Plantinga on this before!). Still, I don't think Kant's criticism of existence as a predicate is convincing.


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