Philosophy Notes
This is the second post in a series that I call Philosophy Notes. Each post is a supplement to my philosophy study guides, designed to help beginning philosophy students read, understand, and think critically about the classic books of philosophy.
The Limits of Philosophy: Descartes and Hume on the Existence of God
In chapter V of Meditations on First Philosophy (1641), Rene Descartes states what is now called the Ontological Argument for the Existence of God. The argument is called ontological because it derives the existence of God not from experience or matters of fact but from the concept of God. Here is the argument in Descartes’ words:
1. The clear and distinct idea of God in my consciousness is the idea of a being whose nature is supreme perfection.
2. I know with clearness and distinctness that an actual and eternal existence pertains to the nature of a supremely perfect being.
3. Therefore, God actually and eternally exists.
The popular version of the argument is much shorter:
1. God is an all-perfect being.
2. Existence is a perfection.
3. Therefore, God exists.
The ontological argument did not begin with Descartes. The first version was stated by Anselm and later repeated by Duns Scotus. In Descartes’ time, it was accepted as valid by Leibniz.
But it was not received well by some contemporaries of Descartes and it was later criticized and rejected by the great philosophers Immanuel Kant and David Hume.
Kant’s counter argument is that existence is not an attribute or property like omniscience or omnipotence. If existence is not a property, then we cannot prove the existence of someone or something by analyzing the concept of that one or thing. For example, I cannot logically derive the existence of 100 dollars from the concept One Hundred Dollars. One hundred real (existing) dollars is the same amount as in the concept. Adding existence to the concept of one hundred dollars does not change the amount in the way that adding one dollar changes the amount and (therefore) changes the concept itself (to One hundred and one dollars).
By analogy, I cannot logically derive the existence of human beings from the concept Human. An analysis of this concepts will not be sufficient to prove that that human beings actually exist. If 100 dollars and humans exist at all, this can only be confirmed by observation and experience, not by concept analysis.
If existence is not an attribute or property of an object, event or person, then being “supremely perfect” cannot imply that a supremely perfect being exists, any more than does being “supremely imperfect” imply that a supremely imperfect being does not exist. Non-existence like existence is not a property.
David Hume has a slightly different approach to the ontological argument. In his Dialogues Concerning Natural Religion, Hume writes that “there is an evident absurdity in pretending to demonstrate a matter of fact, or to prove it by any arguments a priori.” (55). Statements about what does or does not exist are statements about matters of fact not statements about logical relationships between ideas (concepts).
As matters of fact, statements about the existence of God are no different than statements about the existence of the gods of ancient Greece, for example, the existence of Zeus. Such statements cannot be “demonstrated,” as was attempted in the ontological argument presented by Descartes. They can only be proved by observation and experience.
Hume explains in the same quote that to demonstrate that a proposition is true is to prove it by an argument a priori. I can demonstrate (prove) that triangles have three sides because the sentence “Triangles have three sides” relates one concept (triangularity) to another concept (three-sided shape). The relation is one of necessity. To deny that a triangle has three sides is to state a contradiction.
Matter of fact statements are not about relations of ideas (concepts). If I say that 20th century houses have indoor plumbing, I am not stating that the idea of a 20th century house is necessarily related to the idea of indoor plumbing. Instead, I am reporting a fact about 20th century houses that can be proved or disproved by experience and observation. It is a contradiction to say that some triangles have four sides. It is not a contradiction to say that some houses do not have indoor plumbing.
Returning to the ontological argument for the existence of God, if there can be no demonstration of a matter of fact, then any inquiries about the existence of a thing or event is an inquiry about a matter of fact not about a relationships of ideas (concepts). Consider, for example, the concepts Piano and Existence. When we say, “pianos exist,” we are not saying that pianos are things that necessarily exist, that is, we are not saying that existence is tied to the concept of Piano in the same way that three-sidedness is tied to the concept of Triangle. The same thing can be said about “God exists.” Despite Descartes’ dubious claim that existence is a perfection, the existence of anything, be it God or a piano, can only be proved by observation and experience.
If proof of the existence of God depends on observation and experience, then the proof is empirical not analytic. Observation and experience coupled with experiment provide evidence that supports conclusions that are probable not certain. Such proofs are called “inductive” and they belong in the province of science not philosophy.
This did not stop some philosophers from using inductive arguments to prove the existence of God or life after death. In the next episode of “What is philosophy?” we will look at David Hume’s critical examination of the most popular inductive argument: The Design Argument for the Existence of God. We will also show how Hume’s criticism of the Design Argument reveals a fatal flaw of any attempt to prove by inductive argument that there is an afterlife.
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Learn more about Descartes’ ontological argument in Laurence Houlgate’s Understanding Rene Descartes: The Smart Student’ Guide to Meditations on First Philosophy, at https://www.amazon.com/dp/B08MDJTW2K
Learn more about David Hume’s critique of the ontological and design arguments in Laurence Houlgate’s Understanding David Hume: The Smart Student’s Guide to Dialogues Concerning Natural Religion and the Essays on Miracles, Immortality, and Suicide at https://www.amazon.com/dp/B07RN9HQHS
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