A few months ago, I wrote about categories of concepts, and how it's important to keep them straight. Thus "Dog" is a word we use to describe an object with certain characteristics, while "two" is a word we use to describe a grouping of objects, but not an object itself (you can never see a 'two'.) Seems like a lot of philosophical errors come down to crossing these categories -- for instance, the platonic forms treating describers (like "beauty") as real -- more real, in fact, than the things they are used to describe.
Then yesterday, it occurred to me that free will and determinism come down to a similar error. The two are in different categories. Free will is a subjective experience we have in the world -- similar to "pain" or "love." Free will is the experience we all have of choosing a ham or salami sandwich -- of deciding whether or not to give a bum a dime. You cannot see "Free will." There is no "free will box" in the body. You cannot observe an animal and see "free will" at work -- all you see is bodies in motion. Free will is an experience -- a feeling -- a knowledge that you can make your body go either way, depending on what you decide to do.
Determinism, on the other hand, is an unfalsifiable claim about the objective world. It is the claim that everything is invariably caused by something else. But of course this can't be tested at present, because we cannot identify every cause of everything that occurs in the universe. It's not an experience. We don't experience the alleged genes and childhood traumas that force us to select a cheese or salami sandwich. Now don't get me wrong -- we experience the CONDITIONING of our choices -- primarily through habit, but also through compulsive behavior -- but that is different from determinism. Determinism says that everything is decided in advance. Conditioned choices, on the other hand, are our experience that certain choices are more DIFFICULT to make than others, because we experience them as SCARY or UNFAMILIAR or something else. Again, that's experiential. Not deterministic.
Defined this way, free will and determinism do not conflict. If determinism is true, our subjective experience of free will is still true. If determinism is not true, our subjective experience of free will is still true. Demanding that free will be demonstrated in the objective world is just as silly as expecting a child to find the "Two" sitting on the table between two apples, or expecting a doctor to remove the "pain" from my broken arm and place it on the examination bench. Nonsense.
This is compatibilism of a sort, but less rigidly defined than classic compatibilism. Classic compatibilism defines "free will" as "things that are done without external compulsion," despite the fact that they are internally compelled. I don't need to define things that rigidly. My compatibilism holds that determinism is an open question about the objective facts of nature, and free will is a settled question about the universal human experience. They seek to answer two different questions, and are therefore not incompatible with each other.
The key, I think, lies in defining what mean mean by "Free will" and "determinism" as clearly as possible. Within a moment or two, it becomes apparent that what we mean by "free will" is not something that can be observed in the physical sciences -- it is something we know because we feel it. Similarly, determinism is something that could potentially be known through the sciences -- if we were able to compile all facts about the universe into a computer and predict all future outcomes -- but of course we can't yet.
As always appears to be the case, age-old philosophical debates stem from a failure to adequately define our terms.
And I think this modified definition of free will is adequate to serve all its necessary purposes. One of the necessary purposes of free will is in support of moral responsibility. Our sense of justice is offended at the prospect of being punished for actions that were determined, rather than chosen. Free will is significant insofar as it supports a system grounded on moral responsibility -- on reward for good bahavior, and punishment for bad behavior. Without a meaningful free will, there really is no basis for differential treatment for different behaviors. But because we DO actually choose what to do, a world in which bad behavior was rewarded rather than punished would lead people to CHOOSE to engage in much more bad behavior.
But if we acknowledge that free will exists as an experience, if not a physical reality, then it retains its place in our social organization. Whatever the physical reasons, we experience choice. Because we experience it, we must structure our lives and our society around that experience. Good behaviors should be incentivized, so that people are more likely to choose them. Bad behaviors should be disincentivized, so that people are less likely to choose them.
By analogy, "Pain" does not exist in the physical world -- you can't point to it or touch it. It is merely our subjective experience of certain nerve reactions in our system. But that doesn't make it any less real. And medicine needs to take it into account, if it wants to function properly. You can't say, "Well pain isn't a physical entity, so it doesn't exist, and we shouldn't take it into account." It's very real -- but SUBJECTIVELY real. And we ignore it at our peril.
So it is with choice. Whether or not it's one day discovered that all things are ultimately caused by some other physical cause, the fact will remain: we all feel like we have choices, and so our lives and societies will have to take that universal human experience into account.