The question is not so much, “Do we have free will?”, as, “What would free will even mean?" There does not seem to be a way to make the concept of free will coherent. If there is no way to render an idea sensible, then what sense would it make to ask if the idea is correct?
The paradox comes in because I believe we all assume that we have free will, and usually that others do too. And we blame and punish wrongdoers, i.e., criminals, as if they were free do not have committed their crimes. We try to convince others of some idea, or to persuade them to do something, all of which seems nonsensical if their behavior and their thoughts are determined. To complete the paradox, consider that no one can consistently maintain strict determinism, since they would make to make the tacit assumption that they were free to have arrived at that conclusion.
Consider this: you by a new Mac. It comes bundled with software and firmware, that is, an operating system along with a host of standard applications, but of course this all runs on a particular hardware architecture that is presumably identical to all other instances of that particular Mac model. Certain settings are peculiar to your machine, as you fire up the machine and choose preferences and various control panel settings. As time passes, and you begin to use your computer, you create files, and download and install certain additional programs. Very quickly your computer is like no other. The computer acquires what seems to be a “personality”. You yell at it such things as “Oh, come on, I didn’t say to do that”! and so forth, even though you know it is just a machine, doing what its hardware and software dictate it will do. To this, we can in principle add randomness, that is, such things as a power surge, or cosmic ray induced bit flips, and so on, which can cause it to deviate from a predictable path on occasion.
Now I want to make the analogy that the initial state of the machine is like our genetic makeup, with the aforementioned “preferences” added, while the installed software is analogous to what an organism learns and adapts to through experience. So, just as the hardware and installed software entirely determine what the machine will do (excepting the small input from random perturbations), so genetic makeup (“nature”) plus the build up of life experiences (“nurture”) entirely determine how an organism will behave. If you doubt this, please tell me what these other factors might conceivably be.
It does no good to say that there is some kind of “internal you” or “self”, that decides what to do, because we cannot imagine where that self has emerged from other that from experience plus genes. “Nature plus nurture” seem to be the only conceivable process that could have created a conscious self.
Some people have suggested that the existence of a spirit or soul might be injected here to leave room for escaping from the hardware plus software factors. I disagree, because the same problem emerges even then. As long as we postulate that that spirit or soul has a beginning (in some sense, not necessarily temporal), the determining factors would seem to shift to some kind of “supernatural hardware” plus experience (in the natural world plus in the postulated “super-nature” or transcendent realm).
So, what is the proposed “solution”, or “resolution”, I mentioned in the heading? It is, not unexpectedly, difficult to explain. I believe that it is that, to be able to render the concept of determinism coherent, we would have to be outside “the system” of existence we are all in. Only a being outside of that would have the intellectual basis to observe that we are all determined beings, without free will. Since we are all inside, and not outside, nobody can get outside to make the consistent observation that we are all determined. We are trapped, “within the system”, and all have to make (what is at least a consistent assumption) that we are possessed of free-will. But all of us knowing that, at some level of reality beyond the one we have access to, we all have to be determined. In other words, we have no choice but to consider all of human-kind to have free will.
This has perhaps some similarities to the Godelian idea that mathematical systems are either incomplete or inconsistent. Only here we have a concept, “free will”, which cannot really be defined in a coherent manner, but one that we must necessarily assume exists. This appears to be a consistent approach, in that by symmetry everyone can assume everyone else has free will, knowing that our understanding of what it means is fuzzy and incomplete. The opposite position, that everyone is determined, is not a symmetrically consistent ‘solution”, since the person maintaining it would seem be excluding himself or herself as a determined being (since he/she would not have been free to use reason to arrive at that position). This is all an odd state of affairs, to be sure, but we know going in that it has to be, since philosophers have struggled with it with limited success for a good chunk of recorded history.