Physicalism is the idea that the universe is fundamentally composed of entirely blind, deaf, dumb–DEAD–particles in purposeless motion through empty space. For some reason, these dumb particles follow the orders of a system of eternal mathematical laws that, for some reason, the human mind, itself made of nothing more than dumb particles, is capable of comprehending.
If you accept this definition of physicalism and this rendering of the project of natural science, and if you avoid the question of the transcendental conditions of physics, then a coherent non-dualistic physicalist ontology requires that what we call “life” and “consciousness” both be explained away as mere appearances reducible to the mechanical collisions of particles. On this definition of physicalism, “life” and “consciousness” are just words we have for epiphenomenal illusions with no causal influence on what happens. “Life” is a genetic algorithm and “consciousness” is a meme machine, in Dawkins’ and Dennett’s terms. We are undead zombies, not living persons, on this reading of physicalism.
On the other hand, if you see consciousness and life as realities that are impossible to deny and that are in need of explanation *on their own terms*, either as emergent holistic processes with downward causative influence or as intrinsic capacities of phusis itself (my view), then clearly modern physicalism (or what Whitehead calls “scientific materialism”) must be mistaken.
If consciousness and life are not mere illusions with no hand in what happens but active participants shaping the evolutionary journey of the universe, then “physical stuff” like molecules and atoms, stars and galaxies, is not at all what the modern mind has been imagining for several centuries. Matter is not a heap of extensional lumps floating in homogeneous reversible time. That idea of dead matter has always been an idealistic abstraction. Concrete actually existing matter is infinite energy caught in a creative process of spatiotemporal evolution. This energetic expression is experiential through and through, and our special human form of conscious experience is just one of the universe’s many forms of spatiotemporal affection.