A materialist vs. a rationalist
Janis: All our behavior has a physical cause. One day we will discover the biochemical background of everything we do, and then, people will have to realize that free will is an illusion.
Jim: Maybe you are wrong about this, but I'll assume that you are right.
Janis: Oh, you are not as stubborn as I thought.
Jim: So, are you telling me now that I should stop believing in free will because free will doesn't really exist.
Janis: Well, yeah. It is foolish to believe in something that doesn't exist.
Jim: Sorry, my brain chemistry is not allowing me to stop believing in free will.