No actually, all science does not depend on materialism. Prior to material science being a thing, there were the occult sciences which are still practiced around the world today and most definitely fall under the category of science. One can form a hypothesis, make observations, experiment and base their reasoning upon evidence.

Like you said, it's a hypothesis and you still can't explain the hard problem of consciousness via material science. Just because people think that if they slap enough neurons together they'll achieve consciousness, doesn't mean it's true. It's not well supported because there's no evidence that this is the case, just conjecture.