That argument is unsound. The color of the sky depends on atmospheric gases and suspended particles as causal factors. This shows that atmospheric gases and suspended particles are causally potent. At the same time, atmospheric gases and suspended particles do not have libertarian free will. This shows that things can be causally potent without libertarian free will. The statement that "If there is no [libertarian] free will ... The payouts are the same regardless of what you do" assumes that being without libertarian free will entails causal impotence, but that contradicts the fact that things can be causally potent without libertarian free will, as established by the argument about atmospheric gases and suspended particles. Therefore, that statement is false. When that statement has been corrected to allow people to be causally potent without libertarian free will, the conclusion of the argument does not follow.
I think the basis for your counter argument here is flawed.
The statement 'The payouts are the same regardless of what you do' is in the context of a person's state of mind; someone can either 'behave as if there is or behave as if there isn't' free will.
We are for our purposes only concerned about the situation where there is no free will.
The main issue is what not having free will entails. The parent didn't specify 'libertarian' or some other form of free will, and it's hard to specify what it means without resorting to handwaving.
The implied meaning I read was that if a person has no free will, there is no opportunity for them to change what they do. In truth, they are not free to change what they do, or even free to change what they will. Any appearance of such is an illusion.
If we accept that this is what not having a free will means, then it should be clear that, given we have no free will (our assumption from before), whether a person thinks that they have a free will or thinks that they do not have a free will makes no difference, as someone with no free will has no opportunity to change what they do.
Regardless of all that, I think kernel of the idea is a good one. Even if we are deterministic machines with no free will of any kind, we still experience out lives and should enjoy them. Thinking about if we have any oversight of our brain, able to determine the direction we want it to take is a foolish one, driven by the disconnect between what we experience and what we know about the mechanics of our minds. We are our brain, and everything else around it, and what it does is exactly what we are doing. We have the capacity to shape what we think and do as much as any other learning machine, but we are not an outside entity looking in.
My favourite quote about these ideas is this, and I have no idea where it comes from: "If nothing matters, then the statement 'nothing matters' doesn't matter, so you might as well forget about it and enjoy yourself."
"atmospheric gases and suspended particles do not have ... free will"
I believe that gasses and suspended particles do have free will in the same way a brain running on the laws of physics has free will. You're asserting non-free will by appealing to intuitions around a simple example, but it is not justified.
Free will is at a different abstraction level to its implementation. Electrons cannot do arithmetic, but calculators can, with electrons as the implementation.
You misunderstood my argument. I did not assert the existence or nonexistence of libertarian free will or compatibilist free will. Such assertions were beside the point. I was only pointing out that the argument to which I responded contained a logical error. It assumes that "people do not have libertarian free will" entails "people are causally impotent", but the former does not entail the latter.
As an aside, your omission of "libertarian" from the quote of me suggests that you might be conflating two kinds of free will. Because you talk about free will without specifying the kind, the meaning of your reply is ambiguous. Hence, I have trouble agreeing or disagreeing with it. For what it is worth, I do not deny that compatibilist free will can have various degrees of freedom, where the degree is a function of the complexity and arrangement of the things it emerges from. For example, I do not deny that humans, dogs, and cats can be said to have compatibilist free will, nor that the human wills have more degrees of freedom than dog wills and cat wills.
My point is rather that you cannot argue meaningfully about "will" by pointing to physical causality; the two are at different levels of abstraction. It gives absurd results.
