>>12354109I first have to describe two things. The first is a classical universe, and the second is a random universe (which some may call quantum).
Take an empty universe. If it is classical, imagine it contains only two particles. I could describe those two particles mathematically, and could tell you what will happen at any point in time, based on math. However, I am a limited human. If the number of particles is too large, i cant calculate it, but it is calculable (just not by me).
Again, take an empty universe. If the universe is empty, and we put two particles in it, i cannot tell you what will happen with certainty nor with precision in the future. The particles locations and velocities change at random.
Some interpretations of quantum mechanics are essentially classical, others are random.
If my decisions and thoughts are the product of particles moving in my brain, as part of a large universe of particles, it is not free will if they are only a product of classical physics or if they are only a product of randomness. In either case my will is a slave to either a mathematical equation or to a truly random dice.
For free will, my will would have to not be limited by these constraints. Consequently, some people retreat to the idea of a soul giving them free will, and some people say what I wrote in the OP
