Explain and Assess Descartes Ontological Argument.

University Degree Historical and Philosophical studies

Explain and Assess Descartes Ontological Argument

Descartes’ second argument for the existence of God is similar to one that was used by Saint Anselm. The name of the argument was coined by contemporary philosophers after Descartes passed away. Ontology is defined as the branch of metaphysics that deal with the nature of being. Descartes’ Ontological argument of the existence of God is thus based on the nature or essence of God. Descartes was reluctant to use this argument as he thought it might be taken as a sophism. This is because in general, the essence of metaphysical things is separate from their existence.

The ontological argument is a priori proof of the existence of God. This means that it does not rely on any effect (like the idea of God) in the third meditation which has to be caused by God in order to prove His existence. Rather Descartes argues that existence is part of the essence of God. Descartes does this by using the triangle as an example. Whenever one imagines a triangle it follows that there are properties attributed to it. For instance it has three sides, the sum of its angles must equal two right angles and its greatest side subtends its greatest angle. These ideas or essence of the triangle are independent of us and are clearly recognised by the intellect whether we want to or not. Likewise Descartes argues that existence cannot be separated from the essence of God just as the properties of the triangle cannot be separated from it. “It is quite evident that existence can no more be separated from the essence of God than the fact that its three angles equal two right angles can be separated from the essence of a triangle” . Descartes continues that it is “a contradiction to think of God lacking existence”. However, it is objected that existence cannot be taken as a property. For instance Hume argues that the idea of existence is nothing different from the idea of an object. He says that the idea of an existent X is the same as X. This is because the moment we begin to give a predicate to an existent object it is automatically assumed that the object exists. For example if I say that my friend is tall, it must follow that he exists to even qualify as my friend. Therefore if I go on to say that he also exists, there is no new information being communicated. However, Descartes is able to argue that God’s existence cannot be separated from his essence due to how he defines God. God is omnipotent, he is the being besides which nothing greater can be thought of and he is all perfect. It is absurd to think of a God who possesses all perfection not to exist. If he doesn’t exist then he is just a figment of our thoughts which puts him in the same category as Santa Claus. This would mean that he is not the greatest being. The objection that predicating existence as a property does not Convey a new information can also be refuted according to Cottingham. He relates an example of unicorns. Should unicorns be found to exist somewhere, then saying that unicorns exist communicates new information as they have been thought of as mythological objects. But could the idea of a triangle have a nature. Hobbes objects that a triangle cannot have a nature as it is nowhere. Thus we cannot ascribe properties to none existent things. However, Kenny thinks otherwise. In reply to Hume’s objection he says “what exists in no way, neither in the world nor in thought, can have no nature; but the triangle exists in thought and has true and immutable nature that persists whether or not any triangles outside thought exists or cease to be” . Hume’s objection would however be valid if we are to take Descartes’ interpretation. For Descartes, it is not ideas that have true and immutable natures as Kenny suggests but things. He argues that the thoughts or ideas that he has of things such as triangles can not be taken as nothing even if they do not exist outside him. They are not his inventions and therefore have true and immutable natures. But if Descartes is not certain that these things which he has ideas of exist outside him, and it is these things that have true and immutable natures, then Hume is right. In Descartes’ own words something cannot come from nothing. If this is true, then how can we ascribe properties to things that do not exist?

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Some philosophers argue that Descartes defines God into existence. Should we accept the Ontological argument, it would pave the way for all sorts of things to be defined into existence, for instance a winged horse. But Descartes might argue that the wings are not part of the essence of a horse where as existence is inseparable from the essence of God. Whatever belongs to the nature of X is contained in the idea of X. The reverse is however not true. With this Kenny gives an example of a triangle inscribed in a square. This does not follow that it is the nature of a triangle to be inscribed in a square because it is just an idea. The two objects (triangle and square) can be separated. It is an idea put together by our intellect. Whatever is put together by the intellect can be separated by the intellect. On the other hand, the sum of the angles in the triangle must equal two right angles as it is part of the triangle’s essence. But is the idea of God as defined by Descartes not a series of ideas put together by the intellect? We have an idea of perfection and power. This may lead us to think of a being that is omnipotent possessing all perfection. In the case of the winged horse we could decide to give it a different name. A name that suggests that having a wing is an essence of this horse as in the case of Pegasus. One cannot think of Pegasus without thinking of its wings.

Another objection to the Ontological argument comes from Kant who objects to Descartes adding existence to the perfections of God. If Descartes did not add existence to the list of the essence of the triangle why must he add it to the essence of God? However, Kant misses the point. As mentioned earlier on, one cannot list the essence of God and not add existence. He is the supreme being, all powerful all perfect. There is a scholastic argument that suggests that things with the ability to exist do want to exist. This is no less true of the omnipotent God.

So for Descartes the existence of God is necessary. Necessary does not mean that the conclusion is entailed in the premises but necessary is used here to mean that God could not cease to exist, that in fact he has been in existence from eternity. This is because God has the power to exist on his own. In other words he is self-sufficient. But this argument has also come under criticism. If God is self sufficient, then it means he is self-creating. This means that he is his own cause as well as the effect. This is where the contradiction lies. The cause of an effect exists before the effect. So if God is self-creating he must have existed in some form or another before creating himself. But this does not explain the existence of God. As explained by the Causal Adequacy Principle, the cause of an effect must have at least as much reality as the effect. So if God is self-creating, how and in what form did he exist before creating himself.

Moreover, Descartes Ontological argument does not convince us that God exists. All the argument says is that if there is a god, then he must have the essence that Descartes lists (omnipotent, omniscient, all perfect). It is the same as the case of the triangle. A triangle may not exist outside the thoughts of the Meditator but if a triangle exists or whenever it is imagined, then it must have certain properties. So in order to actually prove that a triangle does exist outside his thoughts, the Meditator must provide a convincing proof.

So in conclusion, Descartes has not produced any convincing proofs of the existence of God. What it seems is that Descartes is not proving the existence of God from first principles but making a case for what he already believes in. I agree with Kenny’s conclusion, “Descartes says that his system rests on two principles, his own existence and God’s existence. If my account is right, he cannot have both these principles in quite the way he wants them. If what does not exist can have properties, then he can perhaps prove God’s existence, but not prove his own. If what does not exist cannot have properties, he can perhaps prove his own existence, but he cannot prove God’s existence from God’s essence without begging the question. The cogito and the ontological argument cannot both be valid” .

Descartes Meditations: v-8

Kenny Descartes: a study of his philosophy, p.150

Kenny, Descartes, a study of his philosophy, p.171