I recently read an excellent piece by Raymond Smullyan entitled Is God a Taoist? I particularly like what Smullyan has to say about the concept of free will; here is an excerpt:

Of course, you might well say that the doctrine of free will says that it is you who are doing the determining, whereas the doctrine of determinism appears to say that your acts are determined by something apparently outside you. But the confusion is largely caused by your bifurcation of reality into the "you" and the "not you." Really now, just where do you leave off and the rest of the universe begin? Or where does the rest of the universe leave off and you begin? Once you can see the so-called "you" and the so-called "nature" as a continuous whole, then you can never again be bothered by such questions as whether it is you who are controlling nature or nature who is controlling you. Thus the muddle of free will versus determinism will vanish.

I like that way of thinking about the question of free will: it's quite simple, actually, and yet it provides resolution to what is for so many people a truly vexing and even infuriating puzzle.

That said, here's a totally different thought on the same subject that I myself recently had. It's actually a bit of a paradox.

Consider the question of whether we have free will or our actions are determined by forces outside of our control. Imagine that you have access to every fact about the physical universe—and I mean everything, down to the location and velocity of every individual particle, or probability density, or whatever it takes to be able to say that the conditions are completely known at a particular moment in time—including, of course, the state of every cell, molecule, and atom within my brain (and the rest of my body).

Now let's say at this moment in time, I am faced with a choice. Is it theoretically possible for you to predict what choice I will make?

This is basically the question of determinism, isn't it?

If the answer is yes, then it seems that I must not have free will since my actions were completely predictable. That is to say, I could not have "chosen" to do otherwise; if that were the case, then my action would not have been predictable after all.

On the other hand, if the answer is no, then what does that tell us? Even knowing every fact about the physical universe, you could not predict my choice. So imagine there were a million universes, all in exactly the same condition, and I am faced with the same choice a million times. Doesn't this seem to imply¹ that I might act differently between one universe and the next? After all, if I acted consistently across all million universes, why couldn't you predict it? Yet, if I could act differently in different universes, then there must be an element of randomness in my decision-making!

And if my choice is even partially random, then it seems again that I don't have free will.

So which is it? Are our actions theoretically predictable, or aren't they? And in either case—whether the choices we make are predictable or random—how could we possibly have free will?

Discuss amongst yourselves.