Existence

Once Descartes has "proved" his existence by way of the Cogito argument, and has determined what it is that belongs to his essence of being a thinking thing, he must move to examining questions about the world around him. However, before doing this, he thinks it better to examine the question of the existence of God. If he can prove that he was created by a perfectly benevolent creator, then his innate ideas must carry some semblance of truth, as God is not a deceiver and has placed these ideas in Descartes. Knowledge of God will allow the possibility of achieving understanding of the fundamental principles of the universe.1

Descartes offers two arguments for the existence of God. The first, considered in Meditation Three, is known as the "Trademark Argument." The second, proposed in Meditation Five, is called the "Ontological Argument." This essay will consider the former alone.

The Trademark Argument arises out of the fact claimed by Descartes that there is within each of us an idea of a supreme being, which was placed within us by the thing that created us. The purpose of this idea was to act as the mark of a tradesman placed within us. From examination of this idea, it follows, says Descartes, that God exists. His argument firstly involves the acknowledgement of such an idea within ourselves. This idea of God is one of a being who is "eternal, infinite, omniscient, omnipotent, and the Creator of all things that exist apart from him." This is the first premise of the argument (of course, this has not yet shown that anything corresponding to the idea exists). Secondly, there is the "Causal Adequacy Principle." This principle implies that any object must have as its cause something that contains at least all the attributes of the object if not more. Descartes offers the example of a stone, saying that it cannot be produced by anything that doesn't contain everything to be found in the stone. Similarly, heat cannot be produced by anything that does not contain the same order of perfection as the heat. The purpose of this premise is to reinforce the axiom that nothing comes from nothing.

Descartes then proceeds to apply the Causal Adequacy Principle to ideas. He claims that, just as the cause of objects must contain at least as much reality as the object itself, the cause of an idea must contain at least as much reality, whether "formally" or "eminently" as the idea itself ("formally" meaning actually as represented in the idea; "eminently" meaning in some higher form). In the "Principles of Philosophy," Descartes puts forward the example of a person who has the idea of a highly sophisticated and intricate machine; all the intricacy that is contained in the idea that the person has must be reflected in the source of that idea, whether it be a skilled designer, or the imagination of the person themselves.

Taking these three premises, Descartes arrives at the existence of God as follows: as I have an idea of a perfect being, it must contain in reality all the features that are contained merely objectively in my idea. Descartes himself cannot be the cause of the idea, as he has acknowledged that he is imperfect and ignorant of many things. Neither can the idea have come from an amalgamation of various other ideas that he has, for there would have to be an infinite regress that would in any event trace back to an original cause of the idea, which will contain formally all the perfection present only objectively in Descartes' idea. Hence, the ultimate cause of Descartes' idea of God must possess all the attributes that Descartes perceives it to have, and therefore it can be concluded that God necessarily exists.

The Causal Adequacy Feature is open to counterexamples. Its weakness is that it suggests that there can be no cases of objects being "greater than the sum of their parts." For example, the strength inherent in a bridge must, according to Descartes, be contained in the girders and rivets that make it up. If the bridge did not get its strength from these constituent parts, then it seems that they came from nowhere. We can also say that helium, which is caused by the fusion of hydrogen atoms, possesses properties that were not present in the helium atoms. Finally, Cottingham offers us the example of a sponge cake; its property of "sponginess" is not present in any of the ingredients - the flour, the eggs, etc. but is caused by the chemical reactions that take place when the cake is baked.

Furthermore, in the case of non-material, or efficient, causation there are further counterexamples to the idea of Causal Adequacy. Mersenne questioned Descartes on this point, suggesting the example of the origins of life; if life can emerge from the actions of the sun and the rain, then living creatures can emerge from non-living causes, and thus there is some reality present in the effect that is not present in the cause.

These examples pose problems for modern observers, but Descartes' contemporaries had more difficulty with the third premise of the argument outlined above, namely the application of the Causal Adequacy Principle to ideas. Johannes Caterus, author of the First Set of Objections, asked why ideas should have a cause. However, Descartes appears to be on firmer ground with the principle when applied to ideas than real objects; his idea of a highly intricate machine is elaborated upon by Cottingham, who shows that there would have to be a cause if, for example, a child produced a design for a complex computer. If the child copied it from a book by the designer of the machine, then this merely pushes the argument for finding a cause for the idea back a stage; this example shows that there is as much need for an entity with as much reality as the idea as there is for objects that truly exist in reality.

The suggestion that the child copied the drawing from a book is similar to another criticism by Mersenne that asks why our idea of God should have been placed in us by God, and not have arisen from