Kernel
Chalmers is the figure who named the Hard Problem of Consciousness in 1995 — the question of why physical processes are accompanied by subjective experience at all. The naming was an event. It made a millennium-old philosophical puzzle into a problem that subsequent neuroscience, AI research, and philosophy of mind have organized themselves around.
Contribution
The Hard Problem (1995). The Conscious Mind (1996), still the standard reference. Reality+ (2022), the systematic case that simulated realities are genuinely real. Two decades of work on the relationship between consciousness and information that bridges analytic philosophy and the IIT/Global Workspace empirical traditions.
Civilization-scale significance
The figure in whom the philosophy of mind regains the public-intellectual standing it lost in the mid-twentieth century. Chalmers is the most-cited contemporary philosopher in AI safety, AI ethics, and any room where the question "could this system be conscious?" is being argued seriously.