What Happens to Your Consciousness When You Sleep ? Carl Sagan's Most Unsettling Answer | Carl Sagan

Tonight you will lie down, close your eyes, and disappear. The thing that makes you you — your awareness, your sense of existing — will simply stop. For hours. And then come back. Write your answer in the comments: do you think the you that wakes up tomorrow is the same you that falls asleep tonight? Because what neuroscience has discovered about what happens to consciousness during sleep is one of the strangest things in all of science. In deep sleep, the thalamocortical broadcast that sustains your awareness goes offline completely. There is no one home. In REM sleep, your brain generates a complete reality that you believe entirely — as real as the one you are in right now. And we still do not know why consciousness needs to be absent for the brain to do what it does during sleep. In this video, through Carl Sagan's cosmic perspective, we follow consciousness through the night — and find that what you call yourself is less continuous than you think. What you will learn in this video: 📚 SOURCES: Walker, M. — Why We Sleep (2017) Nedergaard, M. et al. (2013) — Sleep Drives Metabolite Clearance from the Adult Brain — Science Tononi, G. & Cirelli (2014) — Sleep and the Price of Plasticity — Neuron Parfit, D. (1984) — Reasons and Persons — Oxford University Press Descartes, R. (1641) — Meditations on First Philosophy Sagan, C. — The Demon-Haunted World (1995) Sagan, C. — Cosmos: A Personal Voyage (1980) DISCLAIMER: This content adopts the perspective and teaching style of Carl Sagan as an educational tribute. It is not a recording of the historical figure. It is inspired by his belief that the most familiar things — a night's sleep, a morning awakening — contain the deepest questions about consciousness, identity, and what it means to be a mind embedded in a physical universe. #carlsagan #sleep #consciousness #neuroscience #philosophy #dreams #REMsleep #brain #identity #physics #cosmos #science #mind #hardproblem #whatisconscious