Most people, regardless of culture, tend to assume that human beings consist of two fundamentally different components: one bodily, and one immaterial. In contemporary philosophy, this idea is known as “substance dualism.” As a philosophical thesis in and of itself, its premier defender and articulator in the “modern” age was the 17th-century philosopher, scientist, and mathematician René Descartes. For this reason, substance dualism is often called “Cartesian dualism.” It was Descartes that made the famous statement of cardinal philosophical certainty “I think, therefore I am” (cogito ergo sum), and it was in the course of the same ruminations that led him in short order to substance dualism; that, summarily, “I am an essentially thinking thing, therefore I am essentially immaterial thing.” I leave it to the reader to analyze the cogency of this line of thought; for the present purposes, suffice it to say that it has seemed compelling to many.
For the present purposes, I want to say three things about substance dualism: (1) Dualism, as an article of conventional wisdom, seems to come from a deep place within our psyche. (2) This “instinct” of dualism leads directly to some common assumptions and beliefs that are demonstrably false; I will describe three in some detail. (3) Given (1) and (2), the only fitting way to address substance dualism as a philosophical thesis is with as much skepticism as one can muster.
The reason that most people take dualism for granted, I believe, and as I think the following cases will show, is that we just tend to think of ourselves as essentially immaterial beings, without any inherent connection to our physical “bodies.” One may wish to call this tendency an intuition, but it seems to be just a brute instinct, rather than coming from a place of thoughtfulness and reflection. Further, I can testify for myself that when I formulate to my own satisfaction arguments that decisively refute the self-conception that is part and parcel of substance dualism, I nevertheless still find myself with a thoroughly dualistic perception of myself. Substance dualism, therefore, seems to be most fundamentally an incorrigible instinct, rather than a philosophical thesis. Following are three cases which will serve as examples of the dualist instinct, in and of itself, and the out-and-out absurd assumptions it leads to.
“Body Switching” Most people will have seen, or at least are familiar with the premise of, the movie Freaky Friday. In it, a mother and her teenage daughter awake to find that they have “switched bodies:” that the consciousness of one has now inhabited the body of the other. Now, the thing to notice about this, first of all, is how prevalent a fantasy premise this is (there were actually a bevy of “body-switching” movies that came out in the late 80s). Although it is certainly far-fetched and no one knows how this could in fact happen, ordinarily no one would think to object that it is inherently impossible. (It is “logically possible,” as philosophers say, and about things that are just as dubious.)
But think about what such an idea involves from the standpoint of what you know constitutes your person, your self, in actuality. Of course, one is equipped with a brain, and most everyone knows what it’s for: it plays some central and decisive role in what goes on in your mind: your thoughts, personality, consciousness, etc. Some philosophers have argued that thoughts just are brain events, and hence the brain is the mind; it is uncontroversial, at least, that there is certainly at least a strong covariance between mind and brain (the way I would put it is that events in the brain constitute what goes on in your mind). This is of course just an empirical, medical discovery, and the upshot is that there’s no reason to think that anything mental doesn’t depend on your brain. “Body switching,” however, in these movie-type imaginary cases, presumably doesn’t involve brain switching. To be sure, they could have, and there are not-unnotable philosophers who have taken the view that brain-switching would entail switching of whole personalities, as in Freaky Friday, say.
But the important thing to notice is that no one says “But wait, they would have to switch brains!” People just tend to assume, without recourse to causal explanation, that the self is just some immaterial thing that could, in principle, switch bodies. Philosopher Mark Johnston, in a wonderfully down-to-earth paper on the subject of personal identity (cited below), has called this the “bare locus” view of personal identity. This means viewing the self as fundamentally not only immaterial, but also with no inherent characteristics tying it to anything recognizable at all. This view, it seems me, is tantamount to, if not just the same as, substance dualism.
What’s implicit in the bare locus view is that one’s self could in principle just detach from one’s whole body, and even be implanted in a different body, brain and all, still retaining one’s original identity. But to be in someone else’s body and use someone else’s brain, you’d have to be that person! So from what we know about the dependence of mind on brain in any actual circumstance, one can fairly easily see that the imaginary Freaky Friday cases, which are made to seem conceivable by the “bare locus,” dualist, instinct, are inherently and absolutely impossible. So much the worse, it seems, for the bare locus view, and for the kinds of things that dualist instincts tell us about our fundamental nature.
Reincarnation
The idea of reincarnation, although seemingly endemic to Eastern religions, was introduced into Western culture in the last century or so and has found widespread appeal there, too. Philosophically, I find the notion of reincarnation to be fundamentally problematic for at least one major reason. Here’s the problem: What is it supposed to be in me that has no inherent connection with my personality, my gender, or even what species I am, that allows for “me” to “come back as,” say, a fruit fly? What we are staring at face to face is, once again, the bare locus view: that what I am most fundamentally is some uncharacterized consciousness that could conceivably leap from body to body, or be transferred to a brand new body of a member of any animal species whatever. And this is just conceptually incoherent, since it would have to entail that there are no criteria of self-identity I can apply to myself in actuality that characterize my uniqueness in any way other than “the thing that is thinking right now.” (Which is, in fact, just solipsism!) So much the worse for reincarnation, and moreover so much the worse for the “bare locus” view.
The “Why Am I Me?” Question
This last point might seem a little obscure, but I think this is just because it seems to hit at a certain place where the incorrigible dualist instinct really has our imagination locked down; just conceptually, though, it’s simplicity itself. It might just take a few moments to sink in. And when it does, you may well have your mind blown, so have a seat and take a stiff drink.
I remember at an early age thinking, as I would assume most everyone has, “Why am I me??” The idea that this consciousness should reside in this body and not some other seems overwhelmingly arbitrary, doesn’t it? The thought is enough to induce “ontological vertigo” (to borrow a phrase used in quite a different context by Peter van Inwagen). What that thought comes up against is, it seems to me, where consciousness per se and consciousness of self rub up against each other, overlap, and coincide. We try to think of ourselves as possibly “other” rather than “self,” and the “self” that we do find we can’t find any inherent reason to be the way that it is. So we just get this bizarrely dizzy feeling that is induced only by reflecting on self-identity. We find it strange that we are ourselves.
But in fact, the “Why am I me?” question is meaningless and absurd. What on earth could I possibly mean? Well, it’s just this simple: There is no possibility that I could have been someone else. This is just because if I were, then I would not be me. But clearly it’s not possible for me not to be me, because then “I” would be someone else, not me! (reductio ad absurdum) If it just feels too weird to think that way, try referring to yourself in the third person (or to someone else in the third person!), and go through that simple train of thought, trying to consider if you could have been someone else. (Could Micah not have been Micah? Of course not.) That should feel much more straightforward. (What that maneuver seems to show is partly that self-reference is a strangely slippery sort of eel!)
What this necessary truth—that I could not have been someone else—hinges on is necessary identity. Philosopher extraordinaire Saul Kripke forcefully advanced this thesis, in very general terms, back in the early seventies. The notion is so compelling when well-framed that the notion of necessary identity is now widely accepted today among philosophers of otherwise very disparate metaphysical outlooks. Necessity-of-identity just says that, look, there’s no possibility that that wooden table might have been made of ice, because then it wouldn’t have been that table! (The point is exceedingly simple, but sometimes philosophers need to be reminded of obvious truths.) Necessary identity extends to self, obviously; all it takes to see this point is just for one not to be a solipsist, and affirm that oneself is a component of reality equal in existential stature to others like you.
Necessary self-identity has some truly startling consequences. It will be worthwhile to very briefly canvas a few before I drive home the punchline. That I could not have been someone else means that it is meaningless for me to think that I am either “lucky to be me” or “unlucky to be me.” After all, it is absolutely impossible that I might not have been me! Same thing goes for other people, lucky or unlucky in circumstances into which they were born: they could not have failed to be the people they are. I hasten to add that, of course, responsibility can be taken for what happens to people after they begin to exist. None of the foregoing should imply anything like fatalism. It’s just that the question of free will needs to be sharply separated from brute existential fact.
Because of these reasons, I end up firmly convinced—in my mind, at least—that I could not have been someone else. And yet, I find that incorrigible dualist instinct rearing its insistent head: I simply cannot shake the feeling of bizarreness when reflecting on my own self-identity. The question will not be put down, neither by answer nor by force: “Why am I me and not someone else?” It’s strange, and it’s strange that it’s strange, because purely logically such a question should not even arise. What I think all this shows is that the idea of substance dualism comes from a place within us that knows no reason and cannot be argued with, and that from that one should ask any philosophical dualist thesis where it comes from in the first place, and that we should ask it the hardest questions that can be asked of a philosophical thesis. Otherwise, we run the risk of merely being driven by instinct, and that under the guise of direct and careful argumentation. Such would be awfully embarrassing to one who acts as philosopher, or merely as a thoughtful person.
References 1. Mark Johnston, "Human Beings," reprinted in J. Kim and E. Sosa, eds., Metaphysics: An Anthology, pp. 393–407 2. Saul Kripke, "Identity and Necessity," reprinted in J. Kim and E. Sosa, eds., Metaphysics: An Anthology, pp. 72–89; and Saul Kripke, Naming and Necessity (Harvard University Press: 1980)
Originally written: Sunday, August 7, 2005 Updated: Sunday, February 26, 2006
