Dualism and Thinking Things

Dualism Quiz Materials [REQUIRED READING]

A very large percentage of the people with whom I've discussed these issues - over 80% - believe that they have a non-physical mind in addition to having a body. I'd be surprised if the percentage were any lower among the wider American population. So I'm pretty confident that the dominant view among you is that our best examples of thinking things have a dual, or two part, nature.

A still large though somewhat smaller percentage believe that living things have a vital essence, in addition to their physical constitution. So many are dualists about both living and thinking things.

Those of you who have these beliefs have a lot of very good company: most of the best minds of civilization have been dualists of one sort or another, and the view is probably still the majority view among those who have considered the question.

We all know, however, that being widely held is no guarantee of truth. Belief in a flat Earth though once nearly universal is now a recognized falsehood; similarly for a geocentric picture of the solar system. So let us take a closer look at these widely held beliefs.

In this section, I'll focus on dualism about thinking things. As I explained in the section on the meaning of "life," much of what I say will apply to analogous views about living things. To begin, let's see what the sources of dualism are. Then I can state the view itself more clearly. After I've done that, I will present two serious problems for dualism.

First, dualism certainly has a powerful religious motivation. Many religions have as part of their central doctrines the belief that people are both physical and spiritual beings, with one part for each of those two jobs. For example, one familiar group of religions says that minds are temporarily embodied for a while here on Earth, and then, at death, the body and mind separate, with the body staying here on Earth to be disposed of, and the mind going either Up or Down, depending upon how the mind has behaved while embodied. It seems very difficult to make sense of 'life after death' unless we suppose that the surviving part - which, after all, is what determines your identity REQUIRED READING and is the subject of ultimate moral judgment - is nonphysical.

And dualists are not kidding about the mind's being nonphysical: it's not a physical object, it's not a physical process, and it's not a gaseous substance or fluid or energy field. Even if you don't fully understand the most famous formula of the century - E=mc^2 - you should know that it entails that "energy and matter are equivalent," that "energy" and "matter" are two words for the same thoroughly physical subject.

It's worth getting a bit clearer on the contrast between physical and nonphysical, since it's fundamental for dualism.

Suppose you were asked to explain "physical" to someone unfamilar with the term. The usual strategy in explaining unfamiliar terms is to give lots of examples and then to point out that they have some defining characteristic in common. In this case, we can easily think of lots of examples: galaxies, stars, mountains, toasters, bacteria, atoms, electrons, etc. They vary considerably in size. But they all have some size, enormous in the case of a galaxy, very small for an electron.

By the same token, to say that something is not physical is to say that it doesn't have this defining characteristic of physical things; that is, if something is nonphysical, it takes up no space.

It is possible, however, to be both an atheist and a dualist. Descartes gave a simple, powerful argument for dualism using the concept of a self-evident belief that we met in our discussion of faith and evidence. Minds, we found, are knowable in the classically self-evident way. But we also found that bodies are not knowable in this way; recall that it's possible for you to be radically mistaken about which parts yours has. So, there is a real difference between minds and bodies. However closely related they may be at times, they must nevertheless be distinct things. If we add the assumption that, as a complex physical object with many parts, bodies are thereby capable of malfunction, we can conclude that minds are not similarly physical. No theology here.

To help spell things out, here are some handy abbreviations:

M = my mind
B = my body
I = being infallible about some of its current states (that is, sometimes knowable in the classically self-evident way)
P = being complex and physical

So we have:

Descartes's Argument for Distinctness of Mind and Body

(1) M is I
(2) B is not I
(3) Therefore, M is not identical to B.
(4) Anything that's I is not P
(5) Therefore, M is not P

Given the abbreviations used, line (1) says that minds are sometimes knowable in the classically self-evident way. But this does not entail that minds are always knowable in this way. Descartes certainly knew that we can and do make many mistakes about our minds, and would never have claimed that we are always infallible about our minds.

Also, given the abbreviations used, line (2) says that bodies are never knowable in the classically self-evident way.

The inference from (1) and (2) to (3) is guaranteed by the logically necessary general truth sometimes called "Leibniz's Law" (though Leibniz probably had something different in mind):

For any x and any y, and any property F: if x has property F and y does not have property F, then x is not identical to y.

So (3) does follow from (1) and (2). But (3) does not tell us that minds are not physical. To argue for that conclusion, an additional premise, (4), is needed. The justification for line (4) is roughly this: anything that's complex and physical is always capable of malfunction and hence not infallible about any, no less all, of its current states. From this and (3), the conclusion (5) does follow and says that minds are not both complex and physical.

The third source for dualism is found in the ways we commonly describe people, both ourselves and others, for many truths about ourselves and other people are most straightforwardly interpreted on a dualistic model and thus provides evidence for dualism. To give just three examples, consider three very short stories:

In each case, the sentence can be used to express a truth (you can fill out the story), and the truth expressed seems in each case to be about one individual who at one time has 'opposite' characteristics:

S is D and S is not D

but the statement made is flatly self-contradictory - unless the person, S, is really comprised of two distinct components, one of which has and the other of which lacks the characteristic in question:

S's body is D and S's mind is not D.

I'm sure that you can devise thousands of additional examples. Dualism enjoys a real advantage here: it allows us to give a straightforward and systematic account of the truth of all such statements. The dualistic meaning-rule seems to be something like,

In such 'opposites' sentences, "body" refers to the person's (physical) body and "mind" refers to the person's (non-physical) mind.

and with this rule available, the threat of contradiction is replaced by easily gained truth, just as needed.

This is not intended as a proof that dualism is correct, but it ought to be somewhat persuasive since clearly correct alternative meaning-rules are hard to come by. Here's why:

Suppose, for example, that someone proposes this meaning-rule in place of the dualistic one:

In such 'opposites' sentences, "body" refers to the person's physical aspect and "mind" refers to the person's mental aspect.

The trouble with this proposal is not that it's false. Rather, it is too vague for us to be able to tell what it says. Are aspects themselves physical objects? non-physical objects? Are they objects at all? Are aspects physical characteristics of objects? If so, which ones?

A somewhat clearer proposal that may capture the intent of the previous, uselessly vague one is

In such 'opposites' sentences, "body" refers to (most of) the person's body and "mind" refers to the part of the body that is the person's brain (or, central nervous system).

Here at least we have a pretty good idea of what's being said.

But now we can raise a question about its truth. Is it really true that your mental life couldn't take place in anything but the brain you have in your head? Is it that physical object that's essential to your mental life, or is your mental life an information-preserving process that might be able to continue in a different, but functionally similar, thing? (Would that thing even need to be organic, or could it be fabricated from, say, microchips?)

It is the leg that keeps the soul, not the liver as the ancient Chinese believed.

If these suggestions, which have a science-fictional ring, are even plausible, then we may need to take seriously the idea that the brain is not what we're referring to by "mind." Instead, we'd be referring to a process sustainable in different media. And is a process really physical if no particular physical object is required to sustain it?

We'll return to some of these questions in our discussion of the computer model of the mind, aka "Machine Functionalism." The fact that the answers aren't immediately obvious suggests that finding a truly non-dualistic meaning-rule is not quite so easy as it may have seemed.

So, in the truths of common usage, we have a third source of evidence for dualism. And even though it is not conclusive evidence, it can hardly be dismissed.

The clearest and most well-worked out form of dualism was Descartes's: Cartesian Dualism, which can be summarized in five tenets. According to his view,

If we were to stop there, we would have an incomplete form of dualism, because we would have said nothing about how the body and mind influence one another. This is a crucial issue for any theory of thought, because our ability to explain people's actions depends on there being such an influence. One kind of purpose-directed explanation explains people's behavior as based on their beliefs and desires: Jack's hungry and wants some food. He believes that the best way to get some is to cross the street to Jill's Bar and Grill. So, Jack crosses the street. Or: The President wants to get re-elected, and he believes the best way to do that is to increase aid to education, so he increases aid to education.

Since such explanations are so important for many reasons - any hope of doing psychology, sociology, political science, economics, history, human factors engineering, anthropology, analysis of literature, music and the arts depends on having a secure basis for such purpose-directed explanation - we can't leave the sort of influence out and we can't leave it vague. Descartes, who was after all a genius, was aware of this issue, and so he added a fifth tenet, the

Here are two examples, one for each direction of causation:

(i) Being stuck with a pin causes a complex series of electrochemical events in your peripheral and central nervous system, and the last brain event causes the mental event that is the sensation of pain. A series of events in your body causes an event in your mind.

(ii) Wanting to raise your hand is a mental event in your mind which causes electrochemical changes in your brain, and these cause impulses to travel into your arm, chemicals to be released, muscles to contract and, finally, your hand to rise.

Of course, not every event in the body need cause an event in the mind. There are automatic, biomechanical or biochemical processes, like absorbtion of nutrients in the large intestine, that have no direct effect on train of thought. Nor need we suppose that every event in the mind - perhaps, thinking silently to oneself - causes a bodily event. But, V says, interaction does sometimes occur, and it's of the familiar, every-day sort: cause and effect.

So that's Cartesian Dualism. It was designed to respect religious doctrine, it is supported by powerful argument, and it accounts well for common usage. But it also faces two very serious problems.

First, how can the motion of electrons in your brain cause changes in your mind which, by its very nature, takes up no space?

Let's consider the nature of causation - the ordinary cause-effect relationship.

In a game of pool, your aim, to put it crudely, is to get ball 1 to bump into ball 2 and so to change the position of ball 2. Unless you are suspended above the pool table and have extraordinarily good vision, you'll typically not be able to see where ball 1 comes into contact with ball 2. But you know that there must be contact, or ball 2's not going anywhere. The same sort of contact is also required in more complex cases. If you see the result of a head-on collision between two cars, it's generally not feasible to determine where, exactly, all the points of contact were, but you can be sure that there were lots of them.

Sometimes, causation is mediated by a chain of contacts. If you blow on a page of a book, it will deflect even though your mouth does not touch the page. What's happened is that your mouth has moved some air molecules (think of them as tiny pool balls), and they have bumped into others, and ..., and finally some molecules bump into the piece of paper and push it out of its original position. (Think of a row of dominoes falling down.)

Seeing works in much the same way. Particles of light (photons) from the sun or a light fixture bounce off the page, hit your eye and the complex chemical molecules therein, etc.

Even the fanciest physics seems to rely on the pool table model: every force of nature is carried by particles; for example, you remain here on Earth instead of floating off into space because your body and the Earth exchange gravitons, particle exchange that constitutes the force of gravity. It's all a cosmic game of pool.

So, a good slogan about the very nature of causation is: "all causation requires contact," (where it's understood that mediated causation is included). But, according to Cartesian Dualism, minds take up no space, unlike even the smallest of subatomic particles, and they cannot bump into anything that does take up space, e.g., electrons in the nerve cells in your brain.

(Though a common response, it will clearly do no good to "argue" simply that since mental activity is non-physical and occurs in the mind, minds must be non-physical. After all, the main reason for supposing that mental activity is non-physical is the presupposition that minds are the non-physical location for mental activity! One can hardly defend Cartesian Dualism against an objection by presupposing its truth. Any such "defense" would be blatantly question-begging.)

I have heard three replies that attempt to rebut this argument. I'll present them and explain why each comes at a high price.

First reply: The second premise is false. Causation can take place even where there is no possibility of contact. This is a possible reply, but it is so hard to think of non-controversial examples where contact is not involved, that whoever replies in this way owes us an alternative analysis of causation. The analysis would have to tell us why it sure looks like all causation requires contact, but really doesn't. A tall order, especially given the constraint that purpose-directed explanation places on us.

Second reply: The second premise is true, but minds can influence and be influenced by bodies without their interacting causally. So influence is possible, even though causal interaction is not. Again, one might reply in this way, but remember that the postulate of interactionism is part of Cartesian Dualism for a good reason: it serves as the foundation for all explanation of human action. So we must insist on clarity here - the issue is too important to rest with vagueness. And it is not particularly easy to think of alternatives to causation. Descartes was a genius, and he thought of nothing better.

The problem here is not merely a technical one that will get resolved with further progress in science. It's a far deeper, conceptual problem. Here's a helpful analogy: suppose I tell you that I've spent a lovely afternoon imagining brightly colored square circles. I'm so edified by my experience that I urge you to join in the pasttime. How would you react? Although the words I've used are all familiar, as are the concepts they express, they simply don't fit together in the way I've said. What could it possibly mean to say, "I've been visualizing square circles"?! And it won't do any good to hope for advances in psychology or geometry.

In much the same way, when a Cartesian Dualist says she's been thinking about things that take up no space causing changes in things that do, we ought to be deeply puzzled, to demand a coherent explanation, and to be very skeptical about the chances of getting one.

Third reply: Maybe the second premise is false, maybe it's true, but we'll never know which, or why. There is influence of some sort between body and mind, but it is just one of the many mysteries in life how it happens: no matter how hard we try, we will never be able to fathom the mystery; we will never know the answer. This is the desperate Mystery Response, and it exacts the highest price of the three replies, because for fundamental concepts, mystery cannot be quarantined; the disease of ignorance becomes pandemic. (Another metaphor: plunging fundamental concepts into darkness is like dropping a boulder into a small pond - the ripple effect is disastrously large and empties the pond.) In this case, the mystery will infect all explanations of human action. Immediately, we lose our ability to explain human behavior, and with this loss go psychology (pure and applied to, say, education, business management, and therapy), history, political science, literary analysis, sociology, human factors engineering, etc. Not an attractive result. Are you willing to take this plunge into nearly universal ignorance about human beings? Why would anyone buy a theory of mind that deepened ignorance about the mind?!

So there's excellent reason to think that the No Interaction Argument poses a serious problem for dualism.

While this is a common reaction, it comes at an extraordinarily high price which, I would have thought, no religiously motivated Cartesian Dualist would want to pay. I'll explain.

Accepting some statements on faith is, as we found in our discussion of Separation by Foundation, necessary for rationality itself. So every rational person "invokes faith" all the time, even if s/he is a stalwart atheist. However, not just any belief deserves to be accepted on faith, i.e., accorded foundational status. Rather, great caution and high standards are called for (and, as Plantinga suggests, some simple religious beliefs may well qualify as foundational). But they, like any other candidate for foundational status, must qualify. It's not: "anything goes, foundationally."

Here's a story to help emphasize the key point:

Suppose that Mr. Reneé believes about himself: "I have a non-physical soul that interacts causally with my body," and that he accepts this on faith in the aforementioned sense (that is, accords it foundational status). Suppose that Mr. R is made aware of the No Interaction Problem and the Problem of Other Minds and that he is then asked what considerations lead him to continue to hold this belief on faith. Imagine that he replies, "I have no considerations to offer - save for the fact that I've been this way for a long time, like those who raised me - so it's just a matter of BLIND faith for me." That tells the questioner what Mr. R's mind-set is, but it gives the questioner absolutely no reason to adopt that belief in any way, no less to accept it on faith. So replying to the question in this way does not give any persuasive reasons for Mr. R's persisting in his belief - he's told us simply that he insists on persisting. And, Mr. R might add, "I don't care at all if anyone else agrees with me about this matter. I don't even want to try to persuade anyone else. After all my faith is BLIND!"

And many students have in the past responded in just this fashion, with words close to these. But:

Later that same day, Mr. R gets into a heated discussion with Ms. Agnosti about the (im)morality of abortion and euthanasia. REQUIRED READING He vigorously contends that both abortion and euthanasia are morally wrong (at least, almost always), because both what is new in the womb and what is old in the hospital bed are living persons; on Mr. R's dualistic faith, a living person is a human body with a soul. It would be murder, he says, to end a person's life - only the Creator of Souls can properly decide when life ends. And, he insists, there must be laws criminalizing such murders.

Ms. A does not currently believe that persons are ensouled bodies since she does not now believe that there are non-physical souls (though she's keeping an open mind). She reminds Mr. R of the two standard objections to his dualism and asks Mr. R why she should join him in political and social action on these issues. Obviously, it will do Mr. R's cause no good for him to say, "It's just a matter of blind faith for me." That describes his state of mind, but gives no one else any good reason to adopt his attitude.

Of course, it might be that most others believe as Mr. R does and can trounce the minority in a democracy by voting their faith. Or it might be that Mr. R and his fellow believers in souls are in the minority but have a great deal of wealth and power and can force their views on the majority. But unless "might makes right" - a truly repugnant view - none of that would be anything to be proud of. And Ms. Agnosti still shouldn't be persuaded, though she may be forced to behave as if she'd been persuaded.

So, the blind faith response renders dualistic belief politically and socially inert. Typically, however, dualists invest dualism with great moral, political and social significance - it's proposed as a view about the deepest fundamentals of human nature - so they would pay a very high price were they to adopt the blind faith response. And if dualistic views were inert and insignificant in this way, why would anyone take the trouble to maintain and defend them?

Perhaps as bad, if you rely on a blind faith response you seem to have given up the general principle, "If a view's proponents cannot defend the view, then I can reasonably reject the view." What now do you have to say to the members of the North American Man-Boy Love Association (NAMBLA) when they give up on their attempts to defend pedophilia and rest instead with blind faith in its supposed rightness?

What about relying on the Bible or another religious scripture to butress faith? Unless you intend to waste time "preaching to the converted," two conditions must be met if you rely on religious scripture in this way:

(i) You must justify your proffered interpretation of what the Bible (or other scripture) says (something that my colleagues in Religious Studies often find rather difficult, despite being able to read scriptures in their original languages, e.g., Arabic, Chinese, Greek, Hebrew, Hindi, Japanese, Urdu);

and

(ii) You must argue that those in your audience who do not already take what the Bible says for granted ought instead to accept it as reliable and authoritative on these questions about dualism. Otherwise, you would be "preaching to the converted."

So it seems that offering such a scripturally-based defense will be at least as difficult, if not more difficult, than making one of the three replies work. But it might be worth the effort.

[Digression: Separation by Immaterial Causation] REQUIRED READING

---

Even if we can take care of the problem posed by the No Interaction Argument, there is another serious problem for dualism, and it is even broader in scope.

Before presenting the second problem, I'd like to run a brief sanity check.

Consider the following scenario. You arrive home one day to find a loved one deep in anguished thought. She says that she's now convinced that she's the only thinking thing in the world - that all others are merely mindless robots, who act as if they can think, but who engage in no genuine mental activity at all. Wouldn't you take that as an emergency, and try to get help for your loved one? After all, such a belief is obviously crazy. Anyone who takes it seriously does not deserve points for philosophical insight; they need, perhaps, a long rest in a quiet place.

Capgras Syndrome

A DELUSION OF DOUBLES R.J. Berson has reviewed 33 cases of a curious delusion called Capgras' Syndrome. People displaying this syndrome believe that important people in their lives (family members, etc.) have been replaced by exact doubles. No hallucinations or illusions are involved; rather it is a belief. Those afflicted with Capgras' Syndrome may even believe that they themselves are represented somewhere by a double they never see. Not all persons with close emotional ties are believed to be doubled; and these un-replaced persons are always identified accurately. People with these beliefs usually possess normal perceptions and memories but are (obviously) disturbed emotionally with paranoid tendencies. (from: Berson, Robert J.; "Capgras' Syndrome," American Journal of Psychiatry, 140:969, 1983.) Dr. V. Ramachandran on Capgras (and see: Hirstein, W. & Ramachandran, V. S. (1996).  Capgras syndrome:  A novel probe for unravelling the mnemonic functions of the brain.  Proc. of the Royal Society of London, V264, 437-444.) The Fragile Orchestra Links on Capgras Syndrome

Consider a slightly different scenario. This time, your loved one announces excitedly that she has a new, bold, empirical hypothesis, and she wants your help in doing the needed experiments: "There are thinking things - people - besides me! How about that! There's a Nobel Prize in this for us!" This, too, is crazy. Our knowledge that there are other minds is not like our knowledge that, say, there are electrons. It is not mediated by a complex, albeit well-confirmed, theory. Instead, knowing "there's another person right there," is an excellent candidate for foundational belief, one that is normally beyond challenge.

So I hope that we can all agree on this much: any theory of thought that tells us we're rational to take such crazy hypotheses seriously, is itself in serious trouble. Instead, the knowledge that we express with such statements as, "there's a person right there," is very easy to gain. Though such statements are not classically self-evident, they are easy to know, and it's normally grossly irrational to doubt them; hence, they deserve to be foundational.

So, you can see, Cartesian Dualism is in serious trouble. For, according to it, minds are invisible, untouchable and in short, undetectable, and something is a person only if it contains such a mind. Now perhaps you know 'from the inside' that you have (better: are) a mind, but you have no direct access to others' minds - all you have is access to their bodily noises and motions. Those noises and motions might be produced by a mind, but if Cartesian Dualism is true, then it is just as reasonable to assume that they are not so produced. So, if Cartesian Dualism were right about what it is to be a person - namely, a body with an undetectable soul in it - you'd never have the knowledge, "there's another person right there."

This line of reasoning can be summarized in this way:

The first premise is sometimes misread as

If Cartesian Dualism is true, then I am the only thinking thing in the world

-without the essential reference to knowledge of particular thinking things. Of course, Cartesian Dualism does not entail such an absurd consequence ("solipsism"). On the contrary, Cartesian Dualism does allow for the existence of other human minds. But having allowed for their existence, it then makes knowing which bodies to find them in impossible, thus denying us knowledge that other minds are located in many particular places (the human bodies, at least) around us ("there's another person right there").

This second problem is independent of the first. Even if the first can be solved, the second would remain untouched. And it is of broader scope, since it relies only on the supposed nonphysical nature of the mind - an assumption common to all forms of dualism.

If you are sympathetic with dualism, then, I think, you have cause for serious concern. At least, I hope that you will agree that it is worthwhile to look at some alternatives. And that's what we will do.

Next, we will consider a view that is as far from Cartesian Dualism as one can get. It is called "Behaviorism", and it begins by denying the existence of nonphysical minds. After we see Behaviorism's problems - it's got plenty of its own - we will then be in a position to appreciate a way of steering between dualist and behaviorist extremes, the way that drives cognitive science research: Machine Functionalism, aka the computer model of the mind. It is this model that offers the hope of accounting for mental phenomena without using irreducibly purpose-directed explanation.

Additional Sources

Dualism Quiz Materials [REQUIRED READING]

2002 David F. Austin

Go to next section: Behaviorism