physicalism

Physicalism is the philosophical view that everything that exists is physical, and that all phenomena can ultimately be explained in physical terms. In its strongest form, ontological physicalism maintains that the fundamental constituents of reality are physical and that mental states are identical to brain states (reductive physicalism). Non-reductive physicalism holds that while mental properties supervene on physical properties, they are not reducible to them; the brain remains the causal base for mental events, but mental explanations stand at a higher level.

Key ideas associated with physicalism include supervenience (no change in mental properties without a physical change), the explanatory success of the physical sciences, and the aim of a unified ontology. The mind-body problem is central: how can subjective experience arise from physical matter? Proponents appeal to neuroscience, functional and computational analyses, and the apparent progress of physics and biology in accounting for natural phenomena.

Critics argue that physicalism struggles to account for subjective experience, qualitative properties, and intentionality. Thought experiments such as Mary’s room and the prospect of philosophical zombies are often cited in debates about the sufficiency of physicalist accounts. In response, physicalists may defend reductive or non-reductive positions, appeal to emergentism, or argue that experience is itself instantiated by physical processes.

Historically, physicalism has roots in ancient materialism but was developed prominently in modern philosophy and science. It remains a central position in the philosophy of mind, philosophy of science, and metaphysics, continuing to provoke debate and refinement.