At first glance, it appears that this argument stands or falls on the causal adequacy principle. If it is possible for a cause to be less than its effect, then Descartes could indeed by the cause of his idea of God. Moreover, Descartes does not attempt to argue for the causal adequacy principle, but instead simply states that “it is manifest by the natural light”. He appears to have simply inherited the idea from medieval scholastic philosophy, and assumed that everyone would accept it. Philosophers like Bertrand Russell and Bernard Williams have rejected this as an arbitrary rule, which indeed it is, and point out that it should have been subjected to the radical doubt of the First Meditation.
Although this is doubtless a valid criticism, it may still be worth considering whether this argument may not be taken out of its context in Descartes. In this way, the radical that is an essential part of Descartes’ philosophy need not be brought to play. Perhaps the premise that is the causal adequacy principle can be defended against normal doubt even if it is manifestly sceptical to the hyperbolic doubt of the malignant demon hypothesis. We may argue that empirically it is difficult to conceive of an effect that contains something which the cause did not contain. In this case, perhaps the causal adequacy principle may be defensible, but within the context of Descartes’ reasoning in the Meditations, it appears as a bald assumption which Descartes is not in a position to make.
We have seen, then, that this argument falls if the causal adequacy principle is rejected. What we have not yet established is whether the argument stands if the principle is retained. In fact, it does not appear to do so, for the simple reason that Descartes confuses an idea with a real thing. He argues that because he has the idea of a perfect being, there must be such a being to have caused this idea. However, he does not address successfully the possible objection that his idea, being imperfect, could have been caused by a being who was less than perfect. Descartes himself admits that he does not fully understand God. However, he claims that this is not too much of a problem, and states that it is enough that he “understands the infinite”. A critic might ask in what sense Descartes can be said to “understand” something which, by his own admission, he is unable to “grasp”, and might further question Descartes’ certainty that such an imperfect idea originated with a perfect being.
The second argument which Descartes puts forward revolves around the question of his own existence and his own cause. Descartes puts forward two main alternatives: either he caused himself, or something (or someone) else caused him. He rejects the idea that he could have created himself, because, he says, if he had done so he would have been sure to bestow upon himself many perfections which he in fact lacks. Beyond this, we might want to point out the patent absurdity of something causing itself, since to do so such a thing would have to have acted before it existed.
Descartes also pre-empts the critic who may wish to argue that Descartes could have always existed. He argues that a thing is continually being continually preserved, and further that “the distinction between preservation and creation is only a conceptual one”. Therefore, for me to continue in existence requires, according to Descartes, “some cause which, as it were, creates me afresh at this moment”. He therefore feels free to use the same argument he used against the idea that he had created himself at one point in time against the notion that he could be preserving himself through time. This is a weak point in Descartes’ argument, relying as it does on the presupposition that a thing must be continually preserved, and also upon the similarities which Descartes finds between creation and preservation, again something which he says is “evident by the natural light” but which many people would nevertheless wish to doubt.
Descartes moves from this to claim that, since he is a thinking thing with an idea of God, he must have been caused by a thinking thing which also has an idea of God. There are two alternatives. Either this was God, who clearly thinks and has a clear idea of himself, or it was something less perfect that God who thinks and has an idea of God. If the latter, we may ask where this idea of God arose, and the process can be repeated. Eventually, we will arrive at God as the ultimate cause, for “an infinite regress is impossible here” according to Descartes, because he is not looking simply backward in time but also upward in the hierarchy of dependency which exists at the current time and by which Descartes himself is preserved.
This argument has considerable force, but it relies on two ideas which have already been discussed. The causal adequacy principle, by which Descartes establishes that he must have been caused by a thing which thinks and has an idea of God, has already been shown to be inconsistent with Descartes’ epistemological quest. The second thing which must be proved to make this argument true is Descartes’ idea of God, and as has already been seen this is open to question due to the limited nature of Descartes’ knowledge.
Descartes’ third argument is without a doubt the most contentious and certainly the most interesting. Although Descartes himself claimed that his argument was original and differed in important ways to those that went before it, the argument is nevertheless essentially a reworking of Anselm’s ontological argument. Again, Descartes begins with the idea which he has of God as a perfect being, and begins a discussion of God’s essence. It is part of God’s essence, according to Descartes, to exist. Indeed, he goes so far as to say 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”. From this statement, Descartes infers that God and his existence are inseparable, and therefore he is not “free to think of God without existence”.
Anselm states the same argument, albeit rather more elegantly put, in his Proslogion. God is, Anselm says, “a being greater than which none can be conceived”. Now, a being which exists is greater than a being which does not exist. Therefore, if a being greater than which none can be conceived does not exist, it is not a being greater than which none can be conceived, which is a contradiction. Therefore, a being greater than which none can be conceived exists. This being is God.
The ontological argument has been almost universally criticised by philosophers on a number of grounds. Bernard Williams is especially scathing, claiming that modern advocates of such arguments are without excuse. Nevertheless, it is worth examining the ontological argument to see whether it can in fact be defended, if not in its Cartesian incarnation then in some other form.
The argument depends in Descartes upon the idea of essence, although in Anselm this concept is not apparent. For Descartes, the essence of a thing is defined as the things which are essential to the existence of that thing. Norman Malcolm has put forward the idea that a property belongs to the essence of a thing if whenever the property is recalled to mind the thing is also brought to mind, and likewise whenever the thing is brought to mind so is the property. Malcolm uses this position, which he admits is a conjecture but believes to be consistent with Descartes’ recorded philosophy, to support Descartes’ assertion that his essence is to think, that he is in essence a thinking thing. In the case of God, Descartes would want to look a little wider for things which belong to his essence, including such things as omnipotence, omniscience and the like. However, perhaps all of these things could be grouped together as perfection, in which case we can assert that it is the essence of God to be perfect, since if God is truly understood it will be impossible to think of him without also thinking of perfection, and it will be impossible to think of perfection without also thinking of God.
Descartes uses concept of essence as the cornerstone of his ontological argument. He has already shown that his own essence is that of a thinking thing. However, he claims that existence is, generally speaking, distinct from a things essence. Thus, I might be able to say that Descartes’ essence is that of a thinking thing. However, that does not imply (from my, third person, point of view) that Descartes himself in actual fact exists. Likewise, it is part of the essence of a triangle that its three angles are equal to 180 degrees. Now, this does not in any way imply that there is a triangle in existence in the world. All it tells me is that if there were such a thing it would have three angles which would equal 180 degrees.
In the case of God, however, Descartes argues that it is impossible to separate his existence from his essence. This is because the essence of God is defined as perfection, and therefore God must possess every perfection, including existence, within his essence. Therefore, it is impossible to consider God without realising that he exists, and God must in fact really exist. Descartes contrasts the essence of God with the essence of a mountain. If we assume that it is the essence of a mountain to be above a valley, it still does not follow that because the valley is inseparable from the mountain that any mountain exists. However, this does not work the same way with God. Substitute God for the mountain, and the idea of existence (which we have already seen belongs to the essence of God as one of his perfections) for the valley, and you cannot say, as you could with the mountain, that it does not follow that just because existence cannot be separated from God that God actually exists. The fact that existence is inseparable from God shows that he does in fact exist.
Some, notably Kant, have argued against this by saying that “existence” cannot be predicated to anything. Existence, Kant says, adds nothing to the description of the thing to which it is supposedly being predicated, and therefore is not a valid predicate. All that we mean when we say, for example, that a mountain exists is that there is in the real world a thing which has the essence of a mountain. Thus a banana may be imagined to contain in its essence the ideas of yellowness, curvedness and sweetness. We shall assume for now that these are the only things that belong to the essence of a banana. Now, if we were to say that the banana existed, on Kant’s view, we would not be saying anything new about the banana, only that in the world there was actually a thing which corresponded to that essence, i.e.. which was yellow, curved and sweet.
This is a powerful objection to the ontological argument, and it bears against both Descartes’ formulation of the argument and Anselm’s. If existence is not a true predicate, then it cannot be part of the essence of God. Further, if existence is not a true predicate then a being which did not exist could be considered to be a being greater than which none could be conceived, since adding existence to its description would not in fact be adding anything at all, and therefore removing existence from its description would not be detracting from it or making it less than a being greater than which none can be conceived. Clearly, if existence is not a predicate the ontological argument falls. However, it is not at all clear that Kant and those who follow him are correct on this point.
In order to prove Kant wrong, it is only necessary to show that predicating existence to something does in fact change that thing, and does not simply state a fact about the world. In order to do so, it will be useful to retain the example of the banana, with its three essential properties of yellowness, curvedness and sweetness. At this point it will be useful to engage in a thought experiment. If one imagines a banana, then, on our description one necessarily imagines yellowness, curvedness and sweetness. That is to say, the banana which is imagined is yellow, curved and sweet. However, we know that the colour yellow is caused by light reflecting off the surface of a thing in a certain way, and it is certain that there is no light in the mind, since it is non-physical. Likewise, the banana in my mind is curved, but in fact there is no space in my mind and so the banana cannot be curved in the usual sense of the predicate, which requires extension. The same is true of sweetness. The banana in my mind is truly sweet, but it cannot be sweet in the way in which we normally consider sweetness, which involves taste buds and the like, which are not present in the mind.
From this example, it seems that there are in fact two distinct predicates which can legitimately be called “yellow”. The same can presumably be said of all predicates. Henceforth, I will distinguish between the predicates of ideas and the predicates of actually existing things by prefacing the former with “i-” and the latter with “e-”. Therefore, we can say that my idea banana (which we could call i-banana) is i-yellow, whereas a real banana (e-banana) is e-yellow. From this, it is clear that existence can be predicated to a thing. In fact, we can have i-existence, which means nothing more than that a thing can be conceived, and e-existence, which means that there is such a thing in the real world. Does e-existence, then, change the makeup of a thing? Most certainly it does, because it allow the thing to bear e-predicates rather than i-predicates. For example, a banana, if predicated with existence, is able to be e-yellow, e-curved and e-sweet. If not predicated with existence, the banana is simply i-yellow, i-curved and i-sweet.
This can be shown once again when we consider that anything which has all the properties of a thing is that thing. That is to say, if G is identical in all ways to F then G and F are one and the same. This would appear to lead to the conclusion that a banana in the mind IS a banana in real life, unless we allow for the inclusion of existence as a real predicate. Only then can we say that there is a difference between the i-banana and the e-banana and that they are not simply one and the same.
Where does this leave God and the ontological argument? If we follow Descartes’ argument through using the concepts discussed above, we see than there is an i-God in Descartes’ mind. This God has all the properties of a perfect being, because that is what is meant by the name “God”. Therefore, since the i-God is inseparable from the concept of existence, there is an e-God. Stated in this fashion, the ontological argument seems defensible.
In conclusion, Descartes’ proofs of God seem to lack the certainty which we would require of something which is to be the basis of epistemology. That this is the role which Descartes has ear-marked for God cannot be doubted. He is unable to escape from solipsism and the threat of the malignant demon without the existence of God. Therefore, we must say that Descartes’ whole project is only as successful as his proofs of God, and these proofs seem at best tenuous and in need of much re-formulation before they can be presented as reliable.