OK, now let’s get Bayesian. If you could fully account for a person’s choices using genetics and measurable environmental variables, you’d count it as a confirmation of determinism, right? Well, if you buy this argument, you also have to buy its mirror image: The harder it is to account for a person’s choices using genetics and measurable environmental variables, the stronger the case for free will.
I see predictive ability as utterly irrelevant to the question of whether or not we have free will.
The standard argument against free will goes something like:
1. Action X is freely chosen by agent A if and only if A could have done other than X
2. All events (including actions) are causally determined; therefore,
3. If agent A performs action X, he could not have done otherwise (from 1 and 2); therefore,
4. Action X is not freely chosen by agent A (from 1 and 3); and by generalization,
5. We do not have free will
In other words, if our actions are entirely caused by a combination of our genes and environment, things we have no control over, our actions are predetermined and therefore not freely chosen. All our choices are belong to the laws of physics.
Some people try to escape this conclusion using indeterminacy at the quantum level to argue against premise 2. This doesn’t work. Even if quantum indeterminacy filtered through to the macro level (doubtful, and if not we could just change premise 2 to ‘all events at the macro level are causally determined’ and reach the same conclusion), it would be pure random chance adding noise to causality. This surely doesn’t give us free will in any meaningful sense.
Imagine a simple robot programmed to kill any human it comes across. Does it have free will? Now imagine that instead of killing every human, it is programmed to flip a coin to decide the fate of those it comes across. Does it have free will now? Surely the answer has to be the same in both cases. Random chance doesn’t give us freedom.
I think free will and determinism are compatible. If we take humans for what they really are, i.e. meat machines conditioned to behave in certain ways by natural selection, the free will problem becomes tractable. There is no brute mental entity making choices in a vacuum, but it is us making choices nonetheless. We are physical things (we are also mental things, but every mental thing is a physical thing, differently described), and the causal determinism of the universe flows through us, as just another part of said universe, to produce our actions. Who we are and the choices we make may be entirely predetermined by the prior state of the universe, but this does nothing to alter the fact that we act based on preferences and reasons.
We could have acted differenetly had we been different people with different preferences and reasons, even if we could not have been different people. It doesn’t matter how we came to be the people we are, only that we are those people and that we make choices. That’s the only freedom we are are ever going to have and I, for one, am grateful for it.