Whole-Brain Emulation

Whole-brain emulation is the hypothetical project of simulating a biological brain with sufficient fidelity that the simulation reproduces the cognitive functions, behavioral repertoire, and subjective states (if any) of the original. It is often treated as a long-term goal of computational neuroscience and a possible route to mind uploading — the transfer of a person's identity to a non-biological substrate.

The closest empirical test case is C. elegans, whose 302-neuron connectome is fully mapped and whose behavior is relatively simple. Despite this, no existing emulation captures the full behavioral range of the living worm. The failure reveals the scale of the challenge: emulation requires not only the connectome but also synaptic dynamics, neuromodulatory state, body-environment coupling, and developmental history. AI systems that simulate neural networks are not emulations in this sense; they are functional approximations that may replicate behavior without replicating mechanism.

Whole-brain emulation is not merely an engineering problem. It is an epistemological boundary: we cannot know whether an emulation is successful unless we already understand what the brain does, and if we understood that, emulation would be unnecessary.