Free choice and reward and punishment

Hello Rabbi Michi,

I have previously read several articles by Prof. Chaim Sompolinsky, a physicist and observant neuroscientist who claims that in light of research in neuroscience and cognition, it is clear that free choice does not exist, and he asserts absolute determinism and materialism.
I once met him and asked him how his theory dealt with reward and punishment, for example. He told me something like this: “Confusing the denial of free choice with the ability to think and make rational decisions of humans is a minefield that many good people fail in. Even in a world that operates according to its nature (perhaps only in such a world) we are affected by the results of our actions and rationally plan our steps so that we may receive reward and avoid loss.”
I will admit, and I will not be ashamed, that I was not able to understand his answer very well.
I would be very happy if you could please help me.
Thank you very much,