Philosophy of Religion

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Kantís Objection to the Ontological Argument

Kantís Background to the Ontological Argument

Immanuel Kant (1724-1804) does not seem to show familiarity with Anselm's version of the ontological argument, and it appears that he is responding to its less impressive forms found in the writings of Renť Descartes (1596-1650) and Christian Wolff (1679-1754). Nonetheless, his objection has historical significance and is often cited by contemporary philosophers as good reason to reject the ontological argument.

Kant thought the ontological argument was flawed. Any argument for the existence of God based on the proposition that a God that exists in reality is greater than a God that only in the imagination is based on a confusion.


According to Kant the confusion lies in the fact that existence is not a predicate. The predicate is that part of a sentence which is not the subject but which gives information about the subject. A predicate might be a single word like ĎJohn laughedí where John is the subject and Ďlaughedí is the predicate. Or a string of words as in the sentence Clare went to school, 'Clare' is the subject and 'went to school' is the predicate. A predicate is a property that a thing can either possess or lack.

Predicates and the Existence of God

When people assert that God exists they are not saying that there is a God and he possesses the property of existence. If that were the case, then when people assert that God does not exist they would be saying that there is a God and he lacks the property of existence, i.e. they would be both affirming and denying Godís existence at the same time. Kant suggests that to say that something exists is to say that the concept of that thing is exemplified in the world. For Kant, existence is not a matter of a thing possessing a property i.e. existence. Existence is a concept corresponding to something in the world.

Kant's objection to the ontological argument is that existence is not a property that can be attributed to beings like we can attribute other properties such as being blue, hard, or round. When we talk about entities existing, Kant contends that we do not mean to add existence as a property to their beings. In other words, the objection seems to be that one cannot go around adding existence as a property to God (or anything else for that matter) in order to define God (or anything else) into existence. Unfortunately, defining my bank account as such a place that contains millions of pounds would not mean that a careful understanding of that definition of Ďmy bank accountí would really make it so. In order to see if that definition were true, we would have to go to an ATM and check the balance of my account and see if it is accurate. Similarly, a definition of God must be checked with reality to see if it is correct.

Kantís Objection to Descartesí Ontological Argument

Descartes had argued that God had existence in the same way as a triangle has three sides. Kant would agree, if you had a triangle then you did indeed have an object with three sides. But if you do not have the triangle, you have neither its three angles or its three sides. If you accept that there is a God, it is logical to accept also that His existence is necessary. But you donít have to accept that there is a God.

Contemporary Views of the Ontological Argument

Kant's objection has been very influential in the ontological argument debate. Philosopher are still divided as to whether or not existence is a predicate. Some thinkers controversially believe that existence can be thought of as a unique property. A modern advocate of the ontological argument is Alvin Plantinga (b.1932) Professor of Philosophy at Notre Dame University, USA. He has forcefully argued that Kant's objection does not conflict with anything in Anselm's argument. For Anselm does not contingently add existence as a property to God and define him into existence. Naturally these objections are contentious, which adds to the intrigue of the ontological argument.

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