Why does determinism rule out free will? From our subjective point of view, we make choices between the different things we value. But without consciousness neither the subjective point of view nor value exist. And so until we can understand the mystery of how consciousness arises out of determinate matter, we cannot hope to understand free-will in a deterministic universe. And I don't think we ever will understand consciousness. Proposals like panpsycism side step the issue (everything has psychical properties)