If I told you that I had a neurological disease which meant that for eight or more hours a day I lost control of my faculties, bade farewell to the outside world, and was subject to complex hallucinations and delusions – such as being chased by a grizzly bear at Stockport Railway Station – you would think I was in a pretty bad way. If I also claimed that the condition was infectious, you would wish me luck in coping with such a terrible disease, and bid me a hasty farewell.
Of course, sleep is not a disease at all, but the condition of daily (nightly) life for the vast majority of us. The fact that we accept without surprise the need for a prolonged black-out as part of our daily life highlights our tendency to take for granted anything about our condition that is universal. We don’t see how strange sleep is because (nearly) everyone sleeps. Indeed, the situation of those who do not suffer from Tallis’s Daily Hallucinating Delusional Syndrome is awful. They have something that truly deserves our sympathy: chronic insomnia.
– “Notes Towards a Philosophy of Sleep,” Raymond Tallis