Philosophy ceases to be philosophy when its claims can be tested empirically. The major branches of science (physics, chemistry, biology, astronomy, etc.) were once considered topics in philosophy, but are no longer. It appears that Philosophy of Mind is currently making this transition.

(Edit: Changed "Theory of Mind" to "Philosophy of Mind"... psychology lingo crept in there for a second)

Absolutely true, however it's a bit overzealous to jump from starting to understand how the brain works to materialistic assumptions about the nature of consciousness of free will.

See, from my perspective it's overzealous to assume that the conscious mind is not materialistic in nature.

With a question as ill-posed as the nature of consciousness, what's reasonable and what's overzealous depends entirely on your perspective.

Yes it's overzealous to assume either way. That's why it's philosophy not science.

Aside from the fact that people didn't talk that way back then, the converse argument also holds true. We always have believed ourselves to be at the apex of knowledge. In 1610 the hubris belonged to the church, today the hubris belongs to those who believe science has all the answers.

The nice thing about science is at least it is actively questioning itself all the time. However individual scientists can easily subscribe to a philosophically materialist viewpoint without adequate evidence simply because they've spent their whole lives devoted to physics. The study of the correlation between the brain and consciousness needs to go much much deeper before they even hope to come close to having a crack at the free will debate.