Descartes - Lecture 7
7. Descartes' Arguments for the Existence of God (continued)
The Ontological Argument
In the Meditations this argument is to be found in Med 5.
Descartes starts with the supposition that if he finds within himself an idea of an x, then every property which he clearly and distinctly perceives on the basis of that idea to belong to x’s really does belong to x’s.
Example – Descartes has the idea of a triangle. He clearly and distinctly perceives (on the basis of that idea) that one property that belongs to triangles is that their longest side lies opposite (subtends) their largest interior angle. This guarantees that it is really true of triangles that their longest side subtends their largest interior angle.
Descartes finds within himself the idea of God, a supremely perfect being.
He clearly and distinctly perceives on the basis of that idea that one property that belongs to God is that of eternal existence. (No being that does not exist throughout all eternity could possibly qualify as God. God is defined as a being who exists eternally.) This guarantees that it is really true of God that he exists eternally; and as eternal existence entails existence at all times, God exists now.
As Descartes himself rather disingenuously points out: ‘At first sight, however, this is not transparently clear, but has some appearance of being a sophism.’ (AT VII 66)
According to Descartes, this impression that the argument is sophistical derives from that we have been accustomed to distinguish between existence and essence in every other case, and hence automatically suppose that this can also be managed in the case of God.
Another less than transparent piece of Cartesian/scholastic terminology.
What is a thing’s essence? It is that quality or set of qualities that belongs to an object and makes it the kind of object that it is. Thus a triangle’s essence is the quality of being a plane figure with three straight sides. Nothing that lacks that quality qualifies as a triangle, and anything that does have that quality is a triangle. Similarly, a circle’s essence is the quality of being a plane figure such that all the points on its circumference are equidistant from the centre.
The notion ultimately derives from Aristotle’s notion of a ‘formal cause’, which specifies the essence of a thing, or ‘what it is to be something’ (Posterior Analytics, Book II, chpt. 11).
Now when we grasp the essence of a triangle, we do not thereby learn anything about whether it exists or not. No overt reference to existence occurs in the list of qualities that specifies the essence of a triangle. Equally nothing in that list of qualities entails any conclusion about the relationship between triangles and the quality of being an existing thing (though we are supposed to be able to see that a specification of what constitutes the essence of a triangle entails that triangles have interior angles adding up to two right angles and have their longest side opposite their largest interior angle). However when we run through the list of qualities that specifies the essence of God, we see that God has the quality of being supremely perfect. And the quality of existing eternally can no more be separated from the quality of being supremely perfect than the quality of being a plane figure with its longest side subtending its largest interior angle can be separated from the quality of being a plane figure with three straight sides. Hence it is, according, to Descartes just as much of a contradiction to think of God lacking existence as it is to think of a triangle lacking the feature of having its longest side opposite its largest interior angle.
Putting the point in terms of the content of our concepts. Descartes is claiming that our concept of a triangle is such that if we assert that triangles do not have the property of having their longest side subtending their largest interior angle, we are asserting something that is necessarily false (false in all possible worlds/situations that can coherently be described). Similarly, if we assert that God does not have property of existing eternally, we are asserting something that is necessarily false. After all, there seems, to be just as tight and as compelling a connection between the quality of being supremely perfect and the quality of existing eternally as there is between the quality of being a plane figure with three straight sides and the quality of being a plane figure whose longest side lies opposite its largest interior angle.(And if it is necessarily false that God does not have the property of existing eternally, it is necessarily true that God has the property of existing eternally. And as eternal existence implies existence now and at all times, it is necessarily true that God exists now.)
Some problems with this argument
Is eternal existence a perfection?
Now it might be suggested that a being A that has the power and internal resources to ensure that it never goes out of existence is more perfect than a being B that lacks those resources. Less clear that existence itself qualifies.
Fictitious natures
Sabre-toothed tiger, a source of fascination to many children but generally thought to be extinct.
Sabre-toothed ultra tiger – let us define this as a sabre-toothed tiger that has the perfection of eternal existence. Thus eternal existence is part of the essence of an ultra-tiger, it is the quality that makes something an ultra-tiger rather than an ordinary sabre-toothed tiger.
Descartes’ version of the ontological argument, though, has seen him arguing that God exists because a specification of God’s essence refers to a quality, supreme perfection, that cannot be conceived of apart from the quality of eternal existence. Nothing that lacks the quality of eternal existence could qualify as supremely perfect. However irrespective of the merits of Descartes’ understanding of the relationship between perfection and eternal existence, it seems absolutely plain that the quality of eternal existence cannot be conceived of apart from the quality of eternal existence. Even the poorest of logicians would readily recognize that nothing that lacks the quality of eternal existence can qualify as possessing the quality of eternal existence. It is apparent, then, that a specification of the essence of a sabre-toothed ultra tiger refers to a quality that cannot be conceived of apart from the property of eternal existence. By parity of reasoning, therefore, ultra tigers exist. However it is absurd that such a conclusion could genuinely be supported by the kind of argument I have just deployed. But as the argument seems formally analogous to Descartes’ ontological argument, it would appear that this latter argument must also be fallacious.
Descartes own response. Arguments of the kind that lead to the conclusion that ultra tiger and other far-fetched entities exist are undermined by the fact that the idea of an ultra tiger is an arbitrary creation of the human mind (a fictitious idea) while the idea of God as a supremely powerful being is an image of a true and immutable nature.
Now it is not immediately clear how this is supposed to eliminate the formal parallels between his argument and my argument. But what, in any case, might be meant by a claim to the effect that an idea is an image of a true and immutable nature?
One Cartesian suggestion seems to be that an idea of a true and immutable nature is one that has logically demonstrable properties that we must recognize whether we wish to or not. (AT VII 64) However it seems that clear that we can deduce from the claim that a sabre-toothed tiger exists that a entity that normally possesses upper canine teeth at least twice as long as any of its other teeth exists. Yet this latter statement was not explicitly stipulated as being true when we first defined an ultra-tiger.
A second suggestion seems to be that an idea of a true and immutable nature is one that has no components that can be isolated from the other components of the idea (First Replies AT VII 117). Thus it might be suggested that the core properties of God (perfect benevolence, omniscience, omnipotence and eternal existence) interlock in such a way that any one of the four both entails and is entailed by any one of the three remaining properties.
Unfortunately this seems both implausible in itself and, as a general principle, incompatible with what Descartes has to say about such things as squares inscribed in circles (AT VII 118).
Thirdly an innate idea – dependent then on the causal adequacy argument?
Any other pattern of support – the transparency of the mind perhaps? Problems here with our awareness of mental powers and the memory scepticism Descartes introduces immediately prior to the cogito.
The Central Weakness of the Ontological Argument
Thomas Aquinas. One cannot postulate the object of the idea (the existence of an object that instantiates or exemplifies a particular idea) and then reject the properties that comprise its essence. But one can refrain from postulating the object and then there is no contradiction involved in saying that nothing exists that has the properties that make up that object’s essence.
In other words essence talk is talk about the properties that exist when something of a particular kind exists. Necessarily a triangle is a three-sided plane figure versus a triangle, if it exists, cannot fail to have the property of being a three-sided plane figure. God necessarily has the property of being supremely perfect versus God, if he exists, cannot fail to have the property of being supremely perfect. And if we interpret talk of God’s essence in this way, the ontological argument is reduced to the following perfectly harmless chain of thought. The essence of God lies in the quality of being a supremely perfect being. Thus God, if he exists, cannot fail to be a supremely powerful being. A supremely powerful being cannot fail to be an eternally existing being, and an eternally existing being cannot fail to exist here and now. Thus God, if he exists, cannot fail to exist here and now. Not really a problem for the atheist!
 Descartes - Lecture 8 |
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