In a recent debate, Rosenberg claims that only the methods of natural science can deliver genuine knowledge, while Williamson rejects Rosenberg’s extreme methodological naturalism and insists that we have genuine philosophical and humanistic knowledge not achievable by hard-scientific methods alone. This paper responds to the debate. I will argue that physicalism, together with contemporary neurocognitive and evolutionary knowledge, implies that some of our intuitions and mental simulations used in the humanities and philosophy are justified methods for achieving knowledge but are (...) practically irreplaceable with hard-scientific methods. That is, extreme methodological naturalism is in conflict with physicalism. The argument also shows that some moderate version of methodological naturalism can be consistent with physicalism. Physicalism is the strong version of ontological naturalism and is supposed to be accepted by strongly committed naturalists like Rosenberg. Therefore, to be self-consistent, these naturalists should adopt physicalism plus a moderate version of methodological naturalism, rather than Rosenberg’s extreme version. (shrink)