I was with a group of religous friends and they started talking about the "true meaning of prayer". I felt like changing the subject so I diverted the conversation to the question of free will. I said that since the brain controls what the body does and the brain is a physical entity which behaves according to the physical laws, it's theoretically possible to predict what someone will do. They were shocked at the idea and responded that: 1) Don't you "feel" that you have free will just as you "feel" that you're alive? 2) There're things in the body beyond the physical world, so physical laws don't matter in the body (ie: "who tells the brain what to do"?) My question is, is this a pointless philisophical argument that should stop here (like the question if god exists - been there already), or is there anything else of scientific value that I can say? Thanks.