It may come as a surprise that only in the last few decades have the affective and experiential components of the mind become a topic of serious philosophical research. One reason may be that the last few centuries of philosophy were dominated by a tradition flowing from René Descartes (1596–1650), whose most famous works focus on the cognitive component of the mind. (To his credit, Descartes did write a book on the affective part entitled The Passions of the Soul, but this work was less influential than his other writings.) While Plato was concerned with how best to live a happy life, Descartes was con-cerned with how best to secure a foundation for our knowledge of the world. His focus on knowledge naturally emphasizes the cogni-tive component of the mind over the affeccogni-tive and the experiential.
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Descartes begins his Meditations on First Philosophy with the obser-vation that he’s not so sure now of a lot of things he took as obvious in his youth. Imagine for instance that you were raised on the Ptolemaic system of astronomy, according to which the Earth is the center of the universe.Then you get to college, only to learn that nothing of the kind is true: The Sun is the center of our solar system, which is a puny bit of a much vaster galaxy that is, in turn, one among unimaginably many galaxies. That realization would come as a shock, not least because it might make you wonder which of your other cherished beliefs you need to overthrow as well. Descartes imagines someone trying to minimize the shock of this realization by responding: “Well look, you can’t doubt that you’re here reading these words or that 2+2=4! What could be more obvious than these things?” Descartes’
reply is both ingenious and disturbing: How can you rule out the pos-sibility that your thoughts are being controlled by some external force that makes you think that you’re awake reading words, and that makes you think that 2 added to 2 gives 4? Anything you might try to use as proof that these things are not happening itself already assumes that you’re not being deceived and so generates our question all over again. For example, you might say, “Well, I can pinch myself and feel the pain, and that will show that I’m awake.” The trouble is that this experience of feeling the pinch could itself be part of a very vivid dream or, instead, could have been planted in your mind by that external force we mentioned above.
Please take a moment to let these questions sink in. At first it will seem crazy to admit that you can’t be quite sure that you’re awake reading words. But if you’ve ever had a very vivid dream you might have been convinced at the time that what it represented was in fact true. (You can be pretty sure this is happening with people you observe yelling, crying, or screaming in their sleep.) Again, if you’ve seen the movie The Matrix, you’ll have a vivid sense of how someone might have experiences that have been synthesized with such accu-racy that she is sure she is living a normal life as a worker in a big city when in fact she is in a pod generating energy for machines! So how do you know that’s not happening to you right now?
I confess I don’t know how to answer this question. I really have no idea what incontrovertible evidence I can point to that would rule out this depressing possibility. I do feel sure that I’m not in a pod gen-erating energy for machines, but I don’t know how to show that I’m not. Descartes thought he could. He asks us first of all to consider the
difference between my seeing an orange and my seeming to see an orange. I may not be able to be sure that I am in fact seeing an orange;
maybe I’m being duped by some malevolent machine into thinking that I am. However, even if I’m being duped, even if my mind is being manipulated by some external force, I can be dead sure that it seems to me as if there is an orange before me. Contemporary philosophers call this process of knowing the contents of our own minds introspec-tion. According to Descartes, even if I am being duped about what is going on outside my mind, introspection never errs: If something is in my mind, such as a pain, an emotion, a thought, or even an appar-ent sensation of something outside of me, then I must be aware of it.
Further, if introspection tells me that something is in my mind, then it is. Whether I can be certain of anything outside of my mind is a question he takes on later.
Not only can I be sure about the contents of my mind, Descartes argues, I can also be sure that I exist. The reason is that, once again, even if I am being deceived mercilessly, I can’t be being deceived without existing. If I’m being deceived, I’m still thinking, and I can’t do that without being there to do the thinking.This line of thought has been enshrined in popular culture to the point of making its way onto T-shirts in the slogan,
Cogito, ergo sum.
This is Latin for the argument:
I am thinking, therefore I exist.
The argument is valid: It’s not possible to think without existing too! In addition, at least while I am considering the question, the premise “I am thinking” seems true. Descartes puts the point nicely:
Here I make my discovery: thought exists; it alone cannot be separated from me. I am; I exist—this is certain. But for how long? For as long as I am thinking; for perhaps it could also come to pass that if I were to cease all thinking I would then utterly cease to exist. (Meditations on First Philosophy, p. 19)
Here Descartes tells me that I can introspect on the fact that I am thinking. From this I may infer that I exist. (He also seems to hold that if I cease to think, I will cease to exist, but this is a further claim that we need not dwell upon here.) So we can be sure of at least
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two things, Descartes argues: the contents of our minds, and, on that basis, that we exist. That might seem a pretty paltry foundation on which to construct a theory of the mind or anything else, but Descartes has further ideas at his disposal. He next gives an elaborate argument for the existence of a GCB that I won’t recapitulate here.
Suffice it to say that this argument makes him certain that a GCB exists. He also gleans from this argument some conclusions about the possibility of evil. Assume with Descartes that error is a kind of evil.
When I am wrong about something—the cause of epilepsy, the reason why my old friend hasn’t called me, the future of the stock market—
that is a failing. Perhaps it is not the worst possible failing, but it does seem a bad thing nonetheless, a shortcoming in the world.This seems to be what Descartes has in mind in thinking of error as an evil. In addition, normally when we are in error it is our own fault: We have miscalculated, drawn a hasty conclusion, or misremembered something.
On the other hand, suppose that we have used our rational faculties to the very best of our abilities. We have checked our calculations again and again, guarded against bias and prejudice, and so on. Descartes holds that if we do all these things, then the GCB would be to blame if we still end up being in error. After all, such an error is an evil, and it can’t be blamed on us. Descartes thinks that in such a case, the GCB would have to be responsible for the error. He formulates this in the famous
Doctrine of Clear and Distinct Perception: Whatever I clearly and distinctly perceive is true.
“Clear and distinct perception” is code for the idea that I’ve done my utmost to ensure that my reasoning is accurate. If I have done that, then the doctrine of clear and distinct perception tells me that I can’t go wrong. Standing on its own the doctrine might look like wishful thinking. However, keep in mind the theological background: If you can be absolutely sure—as Descartes was by the time he formulated his doctrine—that the GCB exists, then you might reasonably con-clude that any evil that there is must be due to mankind; it can’t be due to the GCB lest He be something short of the Greatest Conceivable.
But if that is right, then if I can also be sure that I’ve done my utmost to be intellectually virtuous, then I can’t possibly be wrong.1
1Recalling our discussion of the problem of evil in Chapter 3, you might notice that Descartes is assuming that a GCB would create the very best possible world that was within Its power to create. Recalling our example of the goldfish and the puppies, you might doubt that that assumption is correct.
Now we’re ready to understand Descartes’ legacy for our study of the mind. I’ll bet you can conceive of disembodied existence. Maybe it’s hard to imagine such a thing, just like it’s hard to imagine curved space-time or the size of our galaxy. It nevertheless seems conceivable that a person could survive the destruction of her body. People who think that life after death is at least possible seem to admit this. Further, notice that you can admit this possibility without being a theist. Even an agnostic or atheist might agree that the idea of disembodied existence seems conceivable. Descartes would make this point by saying that we can clearly and distinctly conceive of the mind existing without the body. If that’s right, though, then his doctrine of clear and distinct perception allows us to conclude that the one can exist without the other.
So what? Well, if x and y are identical, then they have all their char-acteristics in common. (This is known as the indiscernibility of iden-ticals.) Hence, if you can find an x and a y that don’t have all their characteristics in common, you can be sure that they are not identi-cal, that is, that they are distinct. Now consider properties having to do with capacities. Take my word for it: My Newfoundland dog can eat an entire Thanksgiving turkey in less than ten minutes. She has that capacity even if she is not exercising that capacity at the moment.
(She happens to be snoozing on the rug right now, but I’m sure she still has that capacity.) So too, Descartes would point out, my mind has the capacity of existing without my body; that was the gist of our conclusion a moment ago, that the mind can exist without the body.
But of course my body doesn’t have that capacity—my body can’t exist without my body. But then my mind and my body have differ-ent properties, and so are not iddiffer-entical. Here is that argumdiffer-ent put more formally:
1. If x=y, then x and y have all their properties in common.
2. My mind has the property of being capable of existing without my body.
3. My body does not have the property of being capable of existing without my body.
4. My mind and my body don’t have exactly the same properties.
5. My mind is not identical to my body.
Notice immediately that this line of reasoning applies not just to my body taken as a whole, but to any part of it, for instance my brain or my central nervous system. (Just reformulate the argument in one
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ergo,
or the other of these terms to see why.) If this is right, then Descartes has happened on an astonishing discovery: There’s more in the world than just physical objects; in addition there are non-physical things like minds!
To see the significance of this conclusion consider the question, what kinds of thing exist? Well, you’ll say, there are everyday objects like tables, chairs, and houses, and there are more esoteric things like quarks, black holes, and electromagnetic forces. Put at the most abstract level, one might say that there are material things—things that are either made of, or are characteristics of, matter. It might seem that this accounts for everything in the universe. Further, it seems incontrovertible that the mind is closely connected with the central nervous system.We know that one can learn a great deal about what is going on in someone’s mind by studying such things as MRI scans of his brain. If Descartes were with us right now he would acknowl-edge this close connection between mind and matter. He would, how-ever, deny that this close connection is the same as identity. He would point out that nothing in the fascinating field of neuroscience under-mines his five-line argument above.
Answers to the question, what kinds of thing exist? start either with a view to the effect that there is one kind of thing, or a view to the effect that there are two kinds of thing. The former types of answer are versions of monism; the latter are versions of dualism. The form of monism claiming that everything is material is, you guessed it, materialistic monism. (History has also seen defenses of idealistic monism, the view that everything that exists is mental.) Dualism, by contrast, holds that there are two kinds of thing in the world, neither reducible to the other, namely, material things and mental things. If dualism is right, then physics, biology, chemistry, and the other phys-ical sciences cannot give us a complete account of everything that there is; while they can account for a great deal, they cannot give us a full account of the class of nonmaterial things, namely, the world’s minds.That’s a pretty big gap.
Please note that I am not saying that Descartes’ dualism is correct.
We aren’t ready to decide that question just yet.What I do want to be clear is that (a) a good deal hangs on whether dualism is true or not, and (b) Descartes’ dualism is not a perverse or frivolous position.
Looking back at the five-line argument above, I’ll bet you’ll be hard-pressed to find where, if anywhere, it goes wrong. Premises 1, 2, and 3 seem eminently reasonable, and the argument is surely valid. In the
last few decades dualism has been lampooned and vilified by many thinkers both within and outside philosophy. What few writers real-ize, however, is that dualism is supported by an argument that is very powerful indeed. If you’re going to reject dualism, you’d better earn the right to do so by making clear where the above argument goes wrong.