Thanks for your interesting response!

First: this may be the bottom of the "reply" chain, and if so I should remind anyone who happens to be reading (probably just you and I at this point, @tom1gorman!) that just because I got the last word does not mean @tom1gorman has no responses.

On meaning in life without free will

You say you are "pointing out" there is no meaning, and again I have to ask why not? You ask for my explanation of where meaning comes from. This is surely a tricky question, and maybe not well-defined - but my implicit answer in the original post is that if your life is still worth living, then it is "meaningful". And I claimed your life would still be worth living (I hope) even if you found out, to your surprise, that you were a robot running a fully deterministic program. "Well you're just running a determined program, so we're going to turn you off!" "But I'm really enjoying this episode of BoJack Horseman, can you just wait until I'm done? Or now that I think of it, until after I have that date Friday night? Or wait, until after I have kids ... wait I'd want to see them grow up ... "

If you have a different criterion for meaning, I would need to hear it. Of course if by your definition life is only meaningful if your actions are free, then you seem to be begging the question at hand.

On choices and persuasion

Again, on my view we make choices. You still get to pick the chocolate ice cream over the vanilla. They just aren't free choices - at least, not free of the type that would justify retributive punishment. For many people (the compatibilists) that's all there is to "free" choice, is that it was our choice, even if determined. That we have choices is not an illusion; what's an illusion is that they're neither caused by past circumstances nor a product of randomness.

Again compare AlphaGo's move 37, which stunned its professional go player opponent. (I'm not a good enough go player to see why.) AlphaGo chose that move based on an incredible variety of complex factors. Maybe there were stochastic elements to the program too, I don't know - but I am confident there was not magical "agent causation" involved, at any rate. I think we choose just like that - at least, different only in degree, not kind.

One such choice I can make is to change my mind about a belief. Just like AlphaGo, I would make this choice based on enormously complex factors, presumably not all of which are transparent to my conscious mind. But for example I might change my mind about whether my keys are on the bookshelf based on (caused by) my new visual evidence of a bookshelf apparently without keys on it. And I might also change my mind based on new reasoning that never occurred to me, as for example provided by someone else. This is all I mean by persuasion. I can be persuaded to change my mind about free will (unlikely I admit but perhaps!) in the same way AlphaGo can be persuaded to give up some territory it had been fighting for by an unanticipated move from its opponent.

On agent causation and science

That's an interesting video but note that they are still explicitly positing agent causation - a special kind of causation that physics is potentially open to, but is hardly proven.

For one thing, there are plenty of physicists who still think the world is causally deterministic - as for example in the "Many Worlds" interpretation, which is gaining traction. But even among those who think otherwise, the main other option is randomness. It is open to the libertarian to say that it's not really random but a special, unobserved agent causation doing. But here is where the burden shifts back to the libertarian. I grant that the inital burden is on the non-libertarian because it feels like we have free will. (It also feels like water is continuous and not particulate, etc.) The non-libertarian shows the libertarian concept of freedom to be empty, unless there's some miraculous other kind of causation in the world for which we have no evidence. Now the burden is back on the libertarian. Physics leaves the possibility of agent causation open - I'll grant that - but it also leaves the possibility of the Flying Spaghetti Monster open. The burden is on the Pastafarian to show that there's good reason to think there is an FSM, and same with the libertarian and agent causation.

On how the free will might "work"

That video, to its credit, eventually tries to address the crux of the problem, which as I keep saying has nothing to do in the end with causal determinism - it's a conceptual problem where it's hard to see how even immaterial angels have free will. The problem is summarized by the dilemma: was that choice for a reason or not?

The video says that to act for reasons leads to "paradoxes", because we might have conflicting reasons! To me this is like saying AlphaGo could never choose a next move, because it might have reasons both to defend this territory and attack on this other part of the board. It has to weigh them and pick the stronger reasons somehow. "Who decides which is stronger?" the video asks. There's obviously no overriding "who" in the case of AlphaGo - in the end its algorithm bottoms out and it makes a best guess based on the total weight of factors, and I think it's the same for us. The video assumes that because the desires are non-physical, there could be no physical factors to choose. But of course that non-physical desire is just what I and the vast majority of philosophers deny. That's the part where you're positing magic.

The video says the reasons cannot play a sufficient role, so the agent "choice" finishes. But this means the choice is not for reasons; there is no reason you picked chocolate over vanilla. Can you be responsible for a choice not made for reasons? How is that different from a choice made randomly?! This is the other horn of the dilemma - again, a dilemma that applies even to immaterial angels. This is why you don't just need the supernatural - you need a supernatural agency that seems conceptually incoherent. You don't just need magic, you need the kind of magic that could make 1=2. This is a very heavy burden for the libertarian to discharge. (I think supernatural magic is already by definition a super-heavy explanatory burden, but I know there are lots of religious types who disagree.) And given that life without free will is not unimaginable (as I sketch), the clear choice is to reject libertarian free will - as most philosophers do.