So is the argument against free will that we are just made the way we are and will make decisions almost like a robot using an algorithm?
Some dude somewhere once said things could be predetermined/inevitable, but there could still be free will. Like, it is a movie but there is still a "why" that is basically free will, rather than the causality being free will. I think that's what the Wachowskis were trying to get at in the Matrix trilogy.
No, that isn't it. It's more of that a coin flip isn't really random, there are physical factors that if all were known (the force of the flip, the rotation, the air pressure, air currents, humidty, etc etc etc) it would be 100 % known how it would land. That randomness is really just a placeholder for information we don't have or don't understand yet. And this would extend to the human experience.
Virtually all the people I have ever heard that believe that free will is an illusion also say that it is a necessary illusion, and that we can only healthily operate assuming it. Otherwise we become very self-destructive, since you lose a sense of identity/agency at all. Which gets really heady and seems contradictory. It probably isn't a 100% all one or the other sort of thing, perhaps because of feedbacks. So think positive?
I think it all will boil down to if we ever discover what being conscious really means. If I am aware of myself and I am aware I have no free will, does that then not mean I have, in a sense, some measure of free will. I will say that the self typing this right now has no free will in me typing this in that all decisions made before this moment, this now, has lead me to typing this. I do believe that in the now I do have choice. I can choose to stop writing right now or not. In the now.
It's an interesting thought exercise for sure. I'm not certain my brain is up to navigating this particular rabbit hole at present, but I find the topic intriguing.
It all depends on how you look at it. If the choices you make were the only choice you could make in that moment every time, are you still really making a choice?