There have been several recent posts on questions of free will and determinism. I am finding a lot to laugh about in those posts, so I am categorizing this one as humor. I will be commenting, in particular on the recent posts by Jerry Coyne (here and here) and on the post by Sean Carroll.
Let’s start with the meaning of “free will”. In the first of those cited posts, Jerry Coyne defines it with:
My own definition is that if one reran the tape of life up to the moment of “choice,” with every physical atom and electron in the same position at that moment, there is free will if one could have chosen otherwise.
In his later post, he defines it with:
Of course, whether the laws of physics are deterministic or probabilistic is, to me, irrelevant to whether there’s free will, which in my take means that we can override the laws of physics with some intangible “will” that allows us to make different decisions given identical configurations of the molecules of the universe.
It is far from clear that these are the same. The first definition makes no mention of scientific laws, while they are prominent in the second definition.
The first of those definitions talks about restarting the tape of the universe “with every physical atom and electron in the same position at that moment.” What does that even mean. If Einstein taught us anything, it is that “same position” is meaningless. We can talk only of relative position, not of absolute partition. And a relative position will be observer dependent. In the second definition, Coyne uses “identical configurations” instead of “same position”. But this, too, is problematic, for what is observed as a configuration will depend on the inertial frame of the observer.
Carroll is more cautious about defining “free will” and acknowledges that people disagree on the definition. He seems to suggest defining it in physical terms, with:
A better question is, if we choose to think of human beings as collections of atoms and particles evolving according to the laws of physics, is such a description accurate and complete?
Based on that suggestion, he goes on to say:
If that’s your definition of free will, then it doesn’t matter whether the laws of physics are deterministic or not — all that matters is that there are laws. If the atoms and particles that make up human beings obey those laws, there is no free will in this strong sense; if there is such a notion of free will, the laws are violated.
People sometimes sit down in a restaurant, and make choices from a menu provided by the waiter. Some people think of such choices as examples of the exercise of free will. When we make a selection from the menu, we are selecting which atoms will be part of our bodies tomorrow. So that analysis based on the behavior of atoms and particles seems rather dubious.
Carroll begins his discussion of determinism with:
Back in 1814, Pierre-Simon Laplace was mulling over the implications of Newtonian mechanics, and realized something profound. If there were a vast intelligence — since dubbed Laplace’s Demon — that knew the exact state of the universe at any one moment, and knew all the laws of physics, and had arbitrarily large computational capacity, it could both predict the future and reconstruct the past with perfect accuracy.
There’s a problem with this way of thinking. Newton’s laws were based on how we observe the universe from within. But you would really need to know the state of the universe as observed from outside. That is, you would need a metaphysical specification of the state of the universe, and that would require a metaphysical specification language. You would have to be talking about how it would look to Laplace’s Demon rather than how it would look to us. Roughly speaking, that would be talking about a God’s eye view, which is already strange when coming from self-declared atheists.
The point here is that determinism is a metaphysical claim. As best I can tell, there is only one way of doing metaphysics, and that is to make stuff up. If you think a particular scientific law is metaphysical, then you are making stuff up. Presumably, the Ptolemaic astronomers thought that their geocentric account was metaphysical. Today, we disagree. Laplace might have thought that Newton’s account was metaphysical, but Einstein disabused us of that view.
Maybe we should give up on trying to do metaphysics.
Continuing beyond the “Laplace’s Demon” comment, Carroll goes on to say:
Even if there is no such demon, presumably there is some particular state of the universe, which implies that the future is fixed by the present.
However, as Einstein taught us, what is seen as a particular state of the universe will be dependent on the inertial frame of the observer. Once again, it looks as if we cannot make sense of “some particular state of the universe” unless we take that to be a metaphysical state. And we still have the same problem, that the best we can do for metaphysics is to make stuff up.