Descartes presents three arguments for God’s existence in the Meditations: a version of the ontological argument; the “preservation” argument, which is an eccentric variation on the idea of God as First Cause; and the “trademark” argument. Each of these is problematic, though each is also more interesting and defensible than it is usually given credit for. I have said something about ontological arguments in a couple of recent posts (here and here), and I might have something to say about the “preservation” argument in a future post. For now let’s consider the “trademark” argument – probably the most maligned of the three.
The basic thrust of the trademark argument is that the idea of God could not possibly have gotten into the mind unless God Himself put it there. Its presence in the mind thus constitutes a kind of divine signature or trademark, and therefore shows that God exists. Like Descartes’ other arguments for God’s existence, the trademark argument starts from premises that can be known by someone in the epistemic situation Descartes finds himself in by the Second Meditation: He knows that he exists as a thinking thing, but so far that’s all he knows. Hence he has to work from knowledge of himself and of his ideas alone if he is to come to know anything else.
Descartes is of course well aware that people first come to learn about God from other people, such as parents. What is at issue is whether this teaching is a matter of introducing into the mind something that wasn’t there before at all, or rather of drawing out of it something that was there already but only unconsciously (like the geometrical knowledge Plato famously has Socrates draw out of the slave in the Meno). Descartes takes it to be the latter. But even if it weren’t, we would still need to ask where our parents got the idea of God, where the people they got it from got it, and so on, and Descartes’ argument is intended to show that one way or another, directly or indirectly, the idea of God could only have originated with God Himself.
How is the argument supposed to work? To understand it requires a prior understanding of several background assumptions that Descartes either borrows from Scholasticism (altering them somewhat in the process) or develops on the basis of Scholastic concepts. The first is his distinction between the formal reality and the objective reality of an idea. A thing’s formal reality might be thought of as analogous to its “form” as that would be understood in Scholastic thought – though only analogous, since Descartes rejects the Scholastic doctrine of formal causes. It is in any event that which a thing has simply by virtue of being the kind of thing it is. Hence all ideas have the same formal reality since, qua ideas, they are all just modes of a thinking substance. Ideas differ in their objective reality, however, insofar as they represent different things – as a contemporary philosopher might say, they differ in their “intentional objects” (and thus are in that sense “objectively” different).
Despite the awkwardness of the terminology, the basic idea is simple enough, and can be understood by comparison with other kinds of representations, such as words or pictures. “Dog” and “cat” are the same kind of thing – they are both words – and thus have the same formal reality. But they differ in what they refer to – the first refers to dogs, the second to cats – and thus differ in objective reality. A blueprint of a house and a blueprint of a computer are the same kind of thing – they are both blueprints – and thus have the same formal reality. But they differ in what they represent – the first represents a house, the second a computer – and thus they differ in objective reality. Similarly, the idea of a stone and the idea of God are the same kind of thing – they are both ideas – and thus have the same formal reality. But they differ in what they represent – the first represents stones, the second represents God – and thus they differ in objective reality. (This marks another respect in which Descartes differs from the Scholastics, who did not regard thought as involving inner “representations.”)
Next we have the distinction Descartes draws between degrees of formal reality, of which there are three: Modes have the lowest degree of formal reality; finite substances have a higher degree; and an infinite substance would have the highest degree of reality. A “mode” would be something like the shape, size, or motion of a stone, which exists only insofar as it inheres in the stone, in contrast to the stone itself which, as a substance, does not inhere in anything. That’s why it makes sense to say “All I’ve got in my pocket is a stone,” but not “All I’ve got in my pocket is the shape of a stone” – there’s no such thing as the shape of a stone apart from a stone which has it. The stone thus has an independent existence in a way its shape, size, motion, and other modes do not, and in that sense has a higher degree of reality than they do. As a finite substance, though, the stone comes into existence and passes out of existence, depends on other things for its existence, and is limited in various other respects as well. In this way it has a lower degree of reality than an infinite substance – namely God, if God exists (which at this point Descartes does not yet claim to have shown, lest he argue in a circle) – which neither comes into being nor passes away, existing necessarily rather than contingently, and without limitations. An idea has a particularly low degree of reality since it is not only a kind of mode, but, qua mode of a thinking substance, something with no mind-independent reality at all (which even the modes of the stone have).
The final background assumption we need to understand is something commentators on Descartes often refer to as the Causal Adequacy Principle, according to which a total efficient cause must have, either formally or eminently, at least as much reality as its effect. This is a variation on the Scholastic Principle of Proportionate Causality (which I discuss and defend in Aquinas). What it means can be illustrated by a simple example. Suppose you come across a puddle of thick, red liquid on the ground near an outdoor water faucet. You know that a leak in the water line could not have caused it all by itself, because a leak might generate a puddle, but not a thick, red puddle, specifically. There had to be an additional factor as well, such as someone’s spilling cherry soda, or perhaps dropping a “fizzy” tablet into the water. For whatever is in the effect must in some way or other be in the cause as well, otherwise it couldn’t have gotten into the effect. Now, it might be in the cause “formally” – that is to say, in the same manner in which it is in the effect – as it is when the cause is red soda and the effect is a red puddle. Or it might be in the cause “eminently,” as it is when the fizzy tablet is not red but has the causal power, by virtue of its chemical structure, to generate redness in a puddle when it hits the water. Moreover, the “reality” of the effect might all be present (either formally or eminently) in a single cause – as when the effect is a puddle of red soda and the cause is a can of red soda – or it might instead be in several causal factors acting together as a total cause – as when the effect is the red puddle and the cause is water from the line together with the fizzy tablet.
When we combine the distinction between degrees of formal reality with the Causal Adequacy Principle, we get the result that any cause can, by itself, produce an effect only of the same or a lower degree of reality. An infinite substance, if there is one, can cause either a finite substance or a mode to exist. A finite substance can cause either another finite substance or a mode to exist, but cannot cause an infinite substance. A mode can cause another mode to exist, but cannot cause a substance, whether finite or infinite. An idea can, all things being equal, cause another idea, but it cannot cause a mind-independent mode to exist. For a cause cannot give what it doesn’t have to give. An idea doesn’t have mind-independence, so it can’t impart mind-independence to anything; mind-independent modes don’t have the stronger kind of independent existence substances have, so they can’t impart such independent existence to a substance; and finite substances don’t have the kind of unlimited, necessary existence an infinite substance has, so they can’t impart this sort of existence to an infinite substance.
When in turn we combine these themes with the distinction between the formal and objective reality of ideas, we get the result that the cause of an idea must have within it as much formal reality as the idea has objective reality. Once again, though the terminology is forbidding if one isn’t familiar with it, the basic idea is fairly simple. Consider again a blueprint for a computer: If you find such a blueprint lying on the kitchen table one morning, you know it wasn’t the dog or your five-year-old son who drew it. The reason is that there is nothing in the “formal reality” of the dog or the five-year-old – in particular, nothing in the mind or the drawing capacities of either – that corresponds to the “objective reality” of the blueprint – that is, the design plan for the computer that is represented by the blueprint. You know that only someone with the requisite knowledge of electrical engineering could have been its ultimate source, that even if someone who had no such knowledge had drawn it, that is only because he had (say) copied it from a blueprint made by someone who did have such knowledge.
Of course, you could also suppose instead that it was drawn from scratch by someone who knew nothing about electrical engineering but just by accident had come up with a diagram that looked like the blueprint for a computer. But in that case you can, for that very reason, no longer regard it as truly a blueprint at all, but instead only as something that looked as if it were a blueprint. If it really is a blueprint, though, really, literally represents a computer, then only someone with the relevant knowledge could have been the ultimate source of the diagram. That is to say, only someone with sufficiently sophisticated concepts could have the “formal reality” to produce a blueprint with the “objective reality” in question.
[I put aside for the moment the question of whether something non-human – another computer, say – could have produced the blueprint, or whether natural selection could produce something of comparable sophistication, in the form of the “program” encoded in DNA. Suffice it for present purposes to note that if either a computer or natural selection could do such things, that could only be because the information that ends up in their products already pre-existed in some form or other in the total cause (i.e. all the relevant causal factors taken together, which might be the computer or natural selection together with other factors). Misguided ID theorists should take note, however, that the issue has nothing whatsoever to do with “probabilities” or with “complexity” per se. It is not “highly improbable” but rather metaphysically impossible for even the slightest bit of information to arise out of a total cause that did not already have it in some fashion, whether “formally,” “eminently,” or “virtually” (as the Scholastics would put it – again, see the discussion of the Principle of Proportionate Causality in Aquinas). I have discussed these issues in earlier posts, here and here.]
Note that it isn’t just that a dog or a five-year-old couldn’t build an actual computer; again, they couldn’t come up with even the blueprint for a computer, since the information content contained in the blueprint is the same as that contained in the computer itself, and that is what the dog and the five-year-old don’t have. And for the same reason, neither could come up with even the idea of a computer merely from the resources they’ve got qua dog or five-year-old. A dog couldn’t come up with the idea no matter how much time you gave it, and a five-year-old couldn’t come up with it unless he first learns a lot more than the typical five-year-old does or is capable of learning.
Now, what about the idea of God? It couldn’t come from some entirely unthinking mode or substance, precisely because they are devoid of any ideas whatsoever and thus can’t impart ideas. So it must come from something that already has within it, in some way or other (whether formally or eminently), ideas or the capacity to generate them. Nor could the idea of God come merely from other ideas all by themselves, apart from a thinking substance which has the ideas. For even the ideas of (say) pure actuality, omnipotence, omniscience, and the like, considered individually, would need to be combined by some mind in order for them together to form the idea of God. That leaves only a finite thinking substance or an infinite thinking substance – that is, God Himself – remaining as the possible ultimate sources of the idea of God. And whatever its ultimate source is must have as much formal reality as the idea of God has objective reality, just as the source of the blueprint for a computer has to have at least the sophistication that the computer itself has (as the mind of an electrical engineer does).
But in Descartes’ view, no finite substance, thinking or otherwise, can possibly have the requisite formal reality. For the idea of God is the idea of something infinite, and finite substances, precisely because they are finite, do not have of themselves the formal reality to generate even the idea of infinity, any more than a dog or a five-year-old could generate all by themselves even the idea of a computer. And this essentially gives us the “trademark” argument, which we can now summarize as follows:
1. I find within myself the idea of God: a supremely perfect [i.e. purely actual] being, infinite, independent, supremely intelligent, supremely powerful, and creator of everything other than Himself.
2. Whatever caused this idea must have at least as much formal reality as the idea has objective reality.
3. But anything other than God has less formal reality than the idea of God has objective reality.
4. So only God Himself could be the ultimate cause of my idea of God.
5. So God exists.
What should we think of this argument? As I have said, it is almost universally rejected, and with scorn. (Though for an interesting recent defense, see Steven Duncan’s The Proof of the External World: Cartesian Theism and the Possibility of Knowledge.) But I think that the scorn, at least, is misplaced. Certainly the background principles are, in my view anyway, correct (or at least their more consistently Scholastic analogues are correct). Those who reject the Causal Adequacy Principle, for example, tend either not to understand it, or are overly impressed with what are in fact easily-answered objections, or perhaps dismiss it merely because it smacks of medieval ideas of the sort that aren’t fashionable in contemporary philosophy.
But there are, nevertheless, some serious objections that can be raised against the trademark argument. An objection that Descartes himself considers is that he could have arrived at the idea of God all by himself merely by negating the idea of what is finite. For example, he could start with the idea of knowledge, which he has to a limited degree, and negate those limits so as to arrive at the idea of omniscience. But Descartes responds that this has things backwards: In his view, the idea of what is finite itself presupposes the idea of what is infinite, just as a boundary presupposes a larger expanse outside the boundary. (Compare: The notion of an imperfect circle presupposes the idea of a circle, which just is the idea of a perfect circle.)
A more serious difficulty, though, is one that John Cottingham raises in his book Descartes. We can grant that a sophisticated blueprint of a computer is beyond the capacity of the average five-year-old to produce. But suppose instead that we came across a drawing of a box-like object with the words “supremely complicated computer” written on it. Here, of course, we might well suppose that the five-year-old could have drawn it. Now, is our idea of God as a supremely perfect being more like the blueprint for a computer, or more like the box-like object with the words in question written on it? If it is more like the former, then Descartes may have a case for saying that it could not have originated with us. But if it is more like the latter, then it seems he does not.
This is an objection a Thomist is bound to take seriously, for from a Thomistic point of view we cannot in the strict sense grasp God’s essence, and thus cannot form an idea of God that captures anything close to what God is like in Himself. This, you will recall, is the reason Aquinas rejects Anselm’s ontological argument, and it would seem to entail a rejection of the “trademark” argument as well. If we fully grasped the divine essence, then we would see from that essence alone that God cannot fail to exist, just as Anselm says; but in fact we do not fully grasp it. Similarly, if we fully grasped the divine essence, we would have an idea of God of which only God Himself could have been the source, just as Descartes says; but, again, in fact we don’t fully grasp it.
Of course, that does not by any means entail that we cannot know that God exists, or that we can know nothing about His nature. We can know that God exists, but (contrary to what Descartes supposes) only a posteriori, through arguments like the Five Ways (when properly understood in terms of the Aristotelian-Thomistic metaphysics underlying them – once again, see Aquinas). And we can know a great deal about the divine attributes, but relatively speaking our knowledge of the divine nature is bound to be more like the five-year-old child’s knowledge of the computer than the electrical engineer’s knowledge of it.
So, Descartes’ “trademark” argument, while of greater interest than it is often given credit for having, ultimately fails. Like Descartes’ “clear and distinct perception” argument for dualism, what’s true in it isn’t new, and what’s new in it isn’t true.