The lights going out
Sleep, dreams, anaesthesia and a divided brain, four ways of asking what has to be present for anyone to be there, then why there is experience at all and whether a machine could have it.
6 stopsDeep to abyss
The order, and why it is this one
Join anywhere. Each stop carries the route with it, so the foot of every question here offers the next one and the way back to this page.
- Why do we sleep?Sleep is found in almost every animal and is dangerous to do in the open, which means it buys something substantial. Several candidate functions have real evidence behind them. Whether one of them is the reason, or whether the question is badly posed, is unsettled.Deepdepth, meaning: Major unanswered questions.Uncertain. Meaningful scientific, historical or philosophical disagreement remains.Read
- Why do we dream?Dreaming is universal and measurable. There is still no agreed account of what it is for, or whether it is for anything.Deepdepth, meaning: Major unanswered questions.Unknown. Humanity does not currently have a satisfactory answer.Read
- Where does anaesthesia take you?General anaesthesia is reliable, common and not understood at the level of consciousness. A person who cannot respond is not necessarily absent, and the index that can tell the difference in a laboratory is not what operating theatres use.Deepdepth, meaning: Major unanswered questions.Uncertain. Meaningful scientific, historical or philosophical disagreement remains.Read
- What makes you one person?Cutting the bundle connecting the hemispheres is done to relieve severe epilepsy, and it leaves the patient recognisably themselves. Classic experiments suggested the operation produces two separate centres of awareness. A 2017 study tested that directly in two patients and reported the opposite, and the field’s own verdict is that neither result settles it.Deepdepth, meaning: Major unanswered questions.Uncertain. Meaningful scientific, historical or philosophical disagreement remains.Read
- Why does anything feel like anything?We can describe in detail what the brain does when you see red. We cannot explain why any of that activity is accompanied by the experience of seeing red rather than by nothing at all.Abyssdepth, meaning: Fundamental questions where our understanding is extremely limited.Unknown. Humanity does not currently have a satisfactory answer.Read
- Could a machine be conscious?There is no validated test for consciousness in a system unlike us, and the usual informal test, asking it, is unreliable on anything trained to produce human text. The approach a 2023 report calls the most promising derives indicator properties from theories of consciousness and checks systems against them, which converts an unanswerable question into a partly answerable one.Abyssdepth, meaning: Fundamental questions where our understanding is extremely limited.Unknown. Humanity does not currently have a satisfactory answer.Read