Philosophy
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LECTURETheinteractionproblem1.docx4
LECTURE: The interaction problem
Recall that the major difficulty facing Cartesian dualism is the interaction problem, the problem of explaining how mind and body, res cogitans and res extensa, can possibly get in any sort of cause and effect relation given how radically different Descartes says they are. It was a major factor in the turn away from Cartesian dualism to materialism. To understand the depth of the problem, it will be helpful to consider some of the odd ways philosophers tried to deal with it.
Malebranche’s occasionalism
Descartes’ follower Malebranche, who we met last time, proposed a famously bizarre solution. To understand it, we need to set out some background ideas. Recall Aquinas’s First Way of arguing for God’s existence, the argument from motion to an Unmoved Mover. The argument holds that things in the world have the causal power they do only because they borrow it from God as First Cause. Just as a stick can push a stone only insofar as someone’s hand moves the stick, so too things in the world can cause other things to happen only insofar as God imparts to them the causal power to act. Hence, the sun can melt ice only insofar as God continuously imparts to it the power to melt things, the cue ball can knock the eight ball into the corner pocket only insofar as God imparts to it the power to move other things, and so on.
So far that should be pretty familiar. Now, there was a view developed by some thinkers in the Middle Ages, known as occasionalism, that took this view about divine causality to an extreme. According to occasionalism, it’s not just that God gives other things the power to produce effects. It’s that God alone is the only thing that ever really produces effects. Hence it’s not that the sun melts the ice, but only with God’s assistance. It’s that God melts the ice, on the occasion when the sun is present. It’s not that the cue ball knocks the eight ball into the corner pocket, but only with God’s help. It’s that God knocks the eight ball into the corner pocket, on the occasion when the cue ball is present. And so on for all the causes and effects we think we see in the world. Only God really causes anything, and everything else is totally inert.
This was a view the mainstream of medieval philosophy rejected. For example, Aquinas rejects it. He thinks that things in the world really do have causal power, even if they must get it from God. But Malebranche is an early modern philosopher who wants to revive occasionalism.
GOD
knows that cue ball causes eight ball
is approaching to move
That brings us to the interaction problem. Malebranche suggests that we apply occasionalism to the relationship between mind and body. If it’s really God who does everything, then we don’t have to explain how mind and body causally interact, because they don’t. For example, when you decide to get the mail, it isn’t your decision that causes your body to walk to the mailbox. It’s God who causes that to happen, on the occasion when you decide to get the mail. When there’s a rumbling in your stomach, that isn’t what causes you to think “I’m hungry.” It’s God who causes you to have that thought, on the occasion when your stomach is rumbling.
And so on for all apparent interactions between mind and body. For Malebranche, mind and body do not really interact with one another at all, but appear to do so because God intervenes continuously to ensure that a given mental event is followed by an appropriate bodily event, and vice versa. So there is no interaction to explain. Problem solved!
“Dude, honest, God’s doing it, not me!”
Well, maybe, or maybe not. Occasionalism has never been popular, and one of the problems with it is that it seems to destroy free will and moral responsibility.
Leibniz’s pre-established harmony
A second approach is represented by the early modern German philosopher Gottfried Wilhelm Leibniz (1646-1716). Here he is:
Yes, it’s a wig
Leibniz defended the theory of parallelism or pre-established harmony. The idea is this. For general metaphysical reasons that would take us too far afield to get into here, Leibniz did not think there was genuine causal interaction anywhere in the natural world. But of course, there seems to be. The reason is that everything in the natural world runs in parallel in a fashion that is analogous to clocks keeping perfectly in sync.
Hence, suppose you had two perfectly identical old-fashioned alarm clocks of the kind with little bells on top:
Suppose further that you wound each of them up, set them to read the same time, and started them at noon. When, an hour later, the first read exactly 1 pm, the second also read exactly 1 pm. When the first read exactly nine minutes after 10 pm, the second also read exactly nine minutes after 10 pm. When the alarm bells on the first went off at exactly 6 am the next morning, the alarm bells on the second went off at exactly 6 am the next morning. And so on.
Now imagine that you removed the bells from the first clock and removed the hour, minute, and second hands from the second clock. The next day, when the first clock reads 6 am, the bells on the second clock would start ringing. If you didn’t know any better and were observing the two clocks, you might think that the first clock’s reading 6 am caused the bells on the second clock to start ringing. But that would be an illusion. In fact, there is no cause and effect relation at all between the two clocks. Rather, what happened is simply that you wound them up in such a way that they are running in sync. There is a parallelism or pre-established harmony that gives the appearance that what happens in the first clock is affecting what happens in the second.
Now, for Leibniz, that is how everything in the natural world is related. It seems that the cue ball is what knocks the eight ball into the corner pocket. But what is really going on is that they are like clocks keeping perfectly in sync. God sets up the world in such a way that as each thing reaches a new stage in its development, parallel events are going on in other things that make them seem causally related. Hence when the cue ball reaches the stage in its history when it moves toward the eight ball, the eight ball reaches the stage in its history where it starts to move toward the corner pocket. It seems like the first causes the second, just as it seems like the first clock in our example causes the bells to ring in the second. But as with the clocks, that is an ilusion, and what is really going on is that the cue ball and eight ball are simply running in parallel, according to a divinely pre-established harmony.
For Leibniz, that is also what is going in with the relation between mind and body. It seems like they interact, but that is not the case. For example, it seems like your decision to get the mail is what causes your body to walk to the mailbox, but that is an illusion. What’s really going on is that when your mind reaches the stage in its history when it has the thought “I’ll go get the mail,” your body reaches the stage in its history when it starts moving toward the mailbox. And so on for every other apaprent mind-body interaction. Mind and body are simply running in parallel, like the two clocks, according to a divinely pre-established harmony.
GOD
Time to get the mail
Mind Body
Like Malebranche, then, but in a somewhat different way, Leibniz solves the interaction problem by denying that there really is any interaction between mind and body in the first place. Hence there is no interaction to explain and the problem disappears.
Epiphenomenalism
Like Malebranche’s occasionalism, Leibniz’s theory of pre-established harmony never caught on. Both are significant, though, insofar as they show the extremes to which some have gone in order to deal with the interaction problem. Much more influential within contemporary philosophy – but arguably no less weird – is a view known as epiphenomenalism. (The related words “epiphenomenal” and “epiphenomenon” are great Scrabble words, by the way.)
The following analogy will help in explaining the theory. Consider an automobile factory. As a car moves along the assembly line, various machines attach various parts and alter the car in various ways. For example, one machine lowers the engine into the car, another sprays paint onto the outside surface of the car, and so on. As they do so, they generate steam that goes out into the atmosphere through the smokestack.
So, some of what these machines cause are effects in the car itself. But some of what they cause has no effect on the car itself. For example, the steam that goes out through the smokestack has no effect on the car. If you somehow got rid of the steam, that wouldn’t alter the car at all. The steam is merely a byproduct of the process that produces the car, and has no influence on the outcome of that process (namely, the car itself). It is what philosophers call an “epiphenomenon.”
Now, according to epiphenomenalism, that is what the mind is like in relation to the body. It is an epiphenomenon. Hence, suppose we consider behavior, like your going to the mailbox. Part of what causes that is, of course, the flexing of the muscles in your arms and legs, and that flexing was in turn caused by the firing of motor neurons. What caused that? Well, other neurons fired in the brain, and that caused the motor neurons to fire. If you trace it back far enough, you might get back to something like the vibrating of your eardrums as sound from the mail delivery truck reached your ears as it drove away.
Common sense would say, however, that at some stage in this process, your conscious thought “I’ll go get the mail” played a role. The noise from the delivery truck reached your ears, your eardrums vibrated, that caused certain neurons to fire, which caused other neurons to fire, and at some stage this caused you to have that conscious thought, and then that thought, in turn, caused other neurons to fire, which ultimately caused your body to move toward the mailbox.
That is what epiphenomenalism denies. It holds that your thoughts and other mental states don’t cause anything at all, any more than the steam from the machinery has any effect on the car. Thoughts and other mental states are epiphenomenal. They are caused by events in the brain and body, but do NOT in turn themselves cause anything in the brain or body or anywhere else. Totally unconscious brain events are what really cause everything you say and do. Consciousness is just along for the ride. It is merely a byproduct of what goes on in the brain and body, and has no effect at all on what goes on in the brain or body. Even if your mind somehow disappeared entirely, your body would still act exactly the same way – you would still say and do exactly the same things – just as the car coming off the assembly line would be the same even if the machinery stopped generating steam.
MIND
a one-way street
BODY
So, there is, according to epiphenomenalism, no interaction between mind and body. The body, and in particular the brain, generates the mind, but the mind in turn does nothing, and in particular has no effect on what goes on in the physical world. Because the same brain events that cause your body to move toward the mailbox cause you to have the thought “I’ll go get the mail,” there is the illusion that mind has an effect on the body. But an illusion is all that it is.
More to the present point, since there is no interaction between mind and body, there is no need to explain any interaction between the two, and the interaction problem disappears.
Descartes, Parallelism, and Occasionalism:
https://www.youtube.com/watch?v=ZVaVoTBT4gs
Carneades.org on What is Epiphenomenalism?:
https://www.youtube.com/watch?v=R4CvNa4ZO_o
Interactionist and Epiphenomenalist Dualism:
https://www.youtube.com/watch?v=hdeu3lK085A
