The Neuroscience of Consciousness

Anil Seth, a leading neuroscientist studying consciousness, presents the provocative thesis that we don’t passively perceive the world around us—we actively hallucinate it. Drawing on research in predictive processing and Bayesian brain theory, Seth explains that perception is the brain’s “best guess” about what’s causing sensory inputs, a controlled hallucination constrained by the world and refined by experience. This framework challenges naive realism and helps explain phenomena from optical illusions to psychedelic experiences to the sometimes-tenuous nature of consensus reality.

Seth extends this model to explain not just how we perceive the external world but how we experience ourselves. The sense of being a self, of having a body, of existing as a continuous conscious entity—all of these are constructed by the brain through integration of sensory signals, prediction errors, and internal models. He discusses experiments with virtual reality, interoception (perception of internal bodily states), and altered states that reveal how malleable these seemingly solid aspects of selfhood actually are. The implications range from understanding psychiatric conditions to developing new theories about what consciousness actually is.

For anyone interested in the hard problem of consciousness—why and how subjective experience arises from physical brain processes—Seth’s talk offers one of the most scientifically grounded and compelling contemporary frameworks. Rather than treating consciousness as a mysterious add-on to brain function, he shows how it emerges from the predictive, self-modeling processes that allow brains to navigate complex environments. The talk manages to be both rigorously scientific and philosophically profound, changing how you think about the nature of reality and your own experience of being.