Descartes

Descartes

Two proofs of God's existence

Although the proof for God's existence in the Third Meditation is well-known, it is nevertheless instructive to take the time to identify the main premises in a way that will lay out a common ground for the ensuing discussion. The first premise of the proof is that the mediator has an idea with an infinite degree of “objective reality”. This idea is, naturally, the mediator's idea of God, an infinite being or, as Descartes sometimes says, an infinite substance. This temptation will be the topic of much of the following discussion, beginning in the next section. First, let us clarify the notion of objective reality and see how the proof proceeds from the sensible premise.

Descartes distinguishes between the “formal reality” of things, and the “objective reality” of ideas of things. Whereas mainstream reality is the mode of being by which a thing is or exists, objective reality is “the mode of being by which a thing is objectively in the intellect through an idea” Both types of reality come in degrees. The difference observed here between finite, and infinite substance is grounded in Descartes' metaphysics. According to which substance is that which exists independently in one of two ways: determinate substance exists independently of everything but God, whereas God, an infinite substance, exists independently of absolutely everything else. It is easy to see how this notion of degrees of formal reality as corresponding to degrees of independent existence can be extended to include modes.

In Descartes' metaphysics, a mode, understood as a property of a substance, depends for its existence on its substance. If the degree, of conventional reality is indeed so tied to independence, it would follow that a finite substance has more formal reality than a mode since a mode depends on a thing that is itself dependent, namely, a finite substance, whereas a finite substance only depends on a thing that is absolutely independent, namely, an infinite substance (Winkler, 466).

How are they different?

The Third Meditation's proof for the existence of God can be understood by having two premises. The Descartes takes himself to be entitled to the second premise on grounds that are by his lights adequate: it is “manifest by the natural light”. We also noted the temptation to read the self-report passage as one in which the Descartes already takes himself to be entitled to the first premise, without the need for any further, special reasoning or argumentation. However, I will argue in the next section that this temptation ought to be resisted.

Transparent, Clear, and distinct

Either because it is simply undeniable that the Descartes has the idea of God or because this is evident from the fact that he understands the words 'God' and 'infinite being'. The Descartes seems to be entitled to the claim that he has an idea of God. A serious problem with this approach is that it seems to be in tension with the possibility of what Descartes calls “materially false ideas”. Ideas such as those of ...