The physicalist project promises to dissolve the mind-body problem by reducing mental phenomena to purely physical processes. We examine whether such reductions can account for the full richness of conscious experience, particularly the stubborn persistence of qualia—the subjective, first-person qualities that seem to resist physical explanation. We begin with behaviorism, which focuses solely on observable behavior while avoiding questions about inner experience. Identity theory takes a different approach, claiming that mental states are simply brain states. Eliminative materialism takes the most radical stance, arguing that our everyday psychological concepts are fundamentally mistaken and destined for scientific elimination. We explore three influential challenges to physicalist orthodoxy: Nagel’s what is it like argument, Jackson’s knowledge argument featuring Mary, the color scientist, and Chalmers’s philosophical zombies with beings physically identical to us but lacking inner experience. These thought experiments converge on Chalmers’s hard problem of consciousness: explaining why physical processes give rise to subjective experience at all. Functionalism takes a different approach, defining mental states by their causal roles within the system. This perspective allows for multiple realizability, meaning the same mental state could exist in biological brains, silicon chips, or any other suitable substrate. On the other hand, representational theories of mind view cognition as the manipulation of internal representations. Finally, the extended mind hypothesis blurs the line between what counts as internal thought and external tools, proving especially valuable for understanding how humans and AI systems create distributed intelligence spanning biological and artificial systems.