There is a lot of truth in Mr. Mercutio's last statement, especially the note about retinal processing. See the classic "What the Frog's Eye Tells the Frog's Brain" by Warren McCulloch (one of the pioneers of AI, and much more, and a fine representative of my alma mater).
However, I just want to waft he possibility, that the science of brains turns out to be a little wierd. Just like causality is challenged on the quantum level, and the relativistic world does not make ordinary sense either, the activities of brains (connected to bodies I agree) may not follow ordinary common sense causality.
Neural interconnections may not turn out to behave according to Newtonian laws, any more than galaxies or electrons. Long experience in perceiving what brains and bodies do, has convinced us that their behaviour is neither completely determined by past events, nor entirely free of them. This might turn out to be correct on the rigorous level as well.
I believe that if such "brain science" with limited causality were better understood, it would lead to entirely new frontiers in psychology (and other fields). And it might end the debate (obvious here) between behaviourists and cognitive psychologists, because the science would embrace the notion of consciousness as a natural process, and yet would establish a theoretical basis for the perception of freedom of action.
I just wonder why everyone here seems to discount that possibility. Is there really contrary evidence?