SUNDAY, DEC 28, 2014 09:00 PM +0900
The truth about free will: Does it actually exist?
NW: The classic description of the problem is this: ‘If we can explain every action through a series of causal precedents, there is no space for free will.’ What’s wrong with that description?
DD: It’s completely wrong. There’s plenty of space for free will: determinism and free will are not incompatible at all.
The problem is that philosophers have a very simplistic idea of causation. They think that if you give the lowest-level atomic explanation, then you have given a complete account of the causation: that’s all the causation there is. In fact, that isn’t even causation in an interesting sense.
NW: How is that simplistic? After all , at the level of billiard balls on a table, one ball hits another one and it causes the second one to move. Neither ball has any choice about whether it moved; their paths were determined physically.
DD: The problem with that is that it ignores all of the higher-level forms of causation which are just as real and just as important. Suppose you had a complete atom-by-atom history of every giraffe that ever lived, and every giraffe ancestor that ever lived. You wouldn’t have an answer to the question of why they have long necks. There is indeed a causal explanation, but it’s lost in those details. You have to go to a different level in order to explain why the giraffe developed its long neck. That’s the notion of causation that matters for free will.
NW: Assuming that you’re not going to rely on Aesop here, how did the giraffe get its long neck?
DD: The lineage of giraffe-like animals gradually got longer necks because those that happened to have slightly longer necks had a fitness advantage over those with shorter necks. That’s where the explanation lies. Why is that true? That’s still a vexed question. Maybe the best answer is not the obvious one that they got long necks so that they could reach higher leaves. Rather, they evolved long necks because they needed them to drink because they had long legs, and they evolved long legs because they provided a better defense against lions.
NW: We’re often interested in intention where this is linked to moral or legal responsibility. And some cases depend on information that we get about people’s brains. For example, there are cases where people had brain lesions that presumably had some causal impact on their criminal behaviour.
DD: I’m so glad you raised that because it perfectly illustrates a deep cognitive illusion that’s been fostered in the field for a generation and more. People say, ‘Whenever we have a physiological causal account, we don’t hold somebody responsible.’ Well, might that be because whenever people give a physiological causal account, these are always cases of disability or pathology? You never see a physiological account of somebody getting something tight. Supposing we went into Andrew Wiles’ brain and got a perfect physiological account of how he proved Fermat’s Last Theorem. Would that show that he’s not responsible for his proof? Of course not. It’s just that we never give causal physiological-level accounts of psychological events when they go right.
What’s special about us is that we don’t just do things for reasons. Trees do things for reasons. But we represent the reasons and we reflect on them, and the idea of reflecting on reasons and representing reasons and justifying our reasons to each other informs us and governs the intentional stance. We grow up learning to trade reasons with our friends and family. We’re then able to direct that perspective at evolutionary history, at artifacts, at trees. And then we see the reasons that aren’t represented, but are active. Until you get the level of perspective where you can see reasons, you ‘re not going to see free will The difference between an organism that has free will and an organism that doesn’t has nothing to do with the atoms: you’ll never see it at the atomic level, ever. You have to go to the appropriate design level, and then it sticks out like a sore thumb.
NW: So we can adopt the intentional stance towards a chess-playing computer, and we probably ought to if we want to beat it at chess, but it doesn’t follow from that that it’s got free will, or agency?
DO: Exactly Those beings with free will are a sub-set of intentional systems. We say ‘free as a bird’, and birds have a certain sort of free will. But the free will of a bird is nothing compared to our free will, because the bird doesn’t have the cognitive system to anticipate and reflect on its anticipations. It doesn’t have the same sort of projectable future that we have; nor does it, of course, engage in the business of persuasion. One bird never talks another bird out of doing something. It may threaten it, but it won’t talk it out of something.
One thing we require of moral agents is that they are not somebody else’s puppet. If you want the buck to stop with you, then you have to protect yourself from other agents who might be trying to control you. In order to fend off manipulation, you should be a little bit unpredictable. So having a poker face is a very big part of being a moral agent. If you can’t help but reveal your state to the antique dealer when you walk into the store, then you’re going to be taken for a ride, you’re going to be manipulated. If you can’t help but reveal your beliefs and desires to everybody that comes along, you will be a defective, a disabled agent. In order to maximize getting what you want in life, don’t tell people exactly what you want.
NW: So freedom, of the important kind, of the kind worth wanting, is freedom from being manipulated. It’s about being in control of your life, you choosing to do things, rather than these things being chosen by somebody else?
DD: Yes. In order for us to be self-controllers, to be autonomous in a strong sense, we have to make sure that we” re not being controlled by others. Now, the environment in general is not an agent, it’s not trying to control us. It’s only other agents that try to control us. And it”s important that we keep them at bay so that we can be autonomous. In order to do that, we have to have the capacity to surprise.
ロケットを発射すれば、月が到着する、なんとなれば、物の動きは、物理法則で、決定しているから、現在の状態がわかれば、将来の状態もわかる、というもの。であれば、人間に自由なんてないんじゃないか？というのが、哲学の問題の一つであるわけで、それに対して様々な応答があるわけだが、これもその一つ。
仮に物理や生理的なレベルで決定付けられているとしても、だからといって、例えば、キリンの首が長い理由を説明できるわけではないし、仮に、どのようにして、Andrew Wilesが、フェルマーの最終定理を証明したか、かれの脳みその生理的状態から説明できたとしても、だからといって、彼がフェルマーの最終定理を証明しなかった、ことにはならない。
人間の自由にとって大事なのは、人間が、思いや欲望をもつ他者から支配・操作されないで、自分で、自分の行動、及び行動の理由を吟味して、それに基づいて行動できるか、どうかであり、その意味では、人間には自由はある、ということであろう。
