The Philosophy of Sleep

The column you’re reading is at least in part the result of an accident – a happy one, I hasten to add. A few weeks ago, I was sitting on a panel with the philosopher Christopher Hamilton, discussing the question of whether a world without pain is an appropriate goal for mankind or whether pain serves some additional positive purpose other than the obvious biological one of directing us away from things that might harm us (a topic, perhaps, for a future column). Meeting Christopher after a long interval reminded me of his excellent book Living Philosophy: Reflections on Life, Meaning and Morality (2001). The volume includes a fascinating essay entitled ‘The Need to Sleep’, where he notes that philosophers have not paid sufficient attention to this extraordinary phenomenon. Well, a decade on, this is the beginning of a response to Christopher’s wake-up call.

For sleep is rather extraordinary. 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 donot suffer from Tallis’s Daily Hallucinating Delusional Syndrome is awful. They have something that truly deserves our sympathy: chronic insomnia.

Since all animals sleep, we assume it has a biological purpose. The trouble is, we don’t know what that purpose is. There are many theories – energy conservation, growth promotion, immobilisation during hours of darkness when it might be dangerous to be out and about, consolidation of memories – but they are all open to serious objections. William Dement, one of the leading researchers of the last century and co-discoverer of Rapid Eye Movement sleep, concluded from his fifty years in the forefront of the field that “the only reason we need to sleep that is really, really solid, is that we get sleepy.”

Philosophers Asleep

It is easy to see why philosophers have, on the whole, avoided talking about sleep. Those who see the aim of philosophy as being to cultivate the most unpeeled mode of wakefulness are likely to treat sleep as an enemy. Hypnophobia was a striking theme in Existentialist thought. “Blessed are the sleepy ones” Nietzsche said sarcastically, “for they shall soon drop off.” And he sometimes endeavoured to do without sleep, on one occasion trying to live on four hours sleep a night for a fortnight. (I read this unimpressed when I was a junior doctor in the 1970s, and my 104-hour-week included periods of up to 48 hours continuously on call.) Jean-Paul Sartre’s Antoine Roquentin, the anti-hero of Sartre’s Nausea (1938), expresses his contempt for the landlord of the café he frequents by observing that “when this man is alone, he falls asleep.” And a character in one of his other novels observes with horror the person opposite him on the train, fast asleep, passively swaying in time to the movement of the carriage, reduced to a material object. This continuation of our lives in the absence of our waking self, in which the living daylights are replaced by the half-living nightlights, is a creepy reminder of the unchosen automatisms upon which our chosen lives depend.

Not only is sleep a reminder of our ultimate helplessness, or even of how circumscribed a place thought sometimes plays in our lives, there is also the fear of contagion, as if talking about sleep might induce it – just as this reference to yawning will get at least 50% of you yawning in the next 15 minutes. (It’s a fact, honest!)

Of course, there is no reason why the mind should not think about its antithesis, nor why super-mindful philosophers should not take an interest in our regular spells of compulsory mindlessness. After all, physicists have devoted much of their extraordinarily brilliant intellectual exertions to clarifying the nature of matter – of what is there, stripped of the kinds of meanings that fill their own consciousnesses. Philosophers, however, have a particular fear of one kind of sleep: the sleep that their own works may induce. Those carefully crafted arguments, the painstakingly revised sentences, expressing insights, so they hope, into the most fundamental aspects of the world, seem less able than a strip cartoon or a gossip column to hold back the reader from a world-dissolving snooze. Honest philosophers know they cannot complain about casting their philosophical pearls before drowsy swine, because they, too, have fallen asleep over the works of philosophers greater than themselves. I speak as a minor player who has sometimes dozed off while reading Heidegger’s Being and Time – possibly the greatest philosophical work of the last century, and the subject of a monograph I published a decade ago, and over which others too have dozed off. On other occasions I have woken with a start to discover that Kant’s Critique of Pure Reason has fallen from my slackening hand. There could be no more profound critique of reason, pure or impure.

For Descartes, cessation of thinking meant ceasing to be an ‘I’, so thoughtless sleep was vexing indeed – a vegetable, organic gap in our spiritual life. As James Hill (to whom I owe most of the contents of this paragraph) pointed out in ‘The Philosophy of Sleep: Descartes, Locke and Leibniz’ (in The Richmond Journal of Philosophy, Spring 2004), Descartes’ view of the mind as a substance did not allow for any pause in the continuity of thought. If the mind were the kind of thing that could be extinguished by the sound of a lecturer’s voice and rekindled by a wet flannel, it would not be worthy of the status of a substance, which should be immune from mere accidents. Descartes therefore concluded that we never stop thinking, even in the deepest sleep; however, in our deepest sleep we do not lay down any memories of our thoughts. Ad hoc or what?

John Locke would have none of it. Empirical evidence, he says, tells us that we do not think when asleep, and that’s the end of the story: “every drowsy Nod shakes [the Cartesian] Doctrine.” Leibniz, anticipating the confusions of Herr Professor Freud, argued that Descartes was right: we are thinking during dreamless sleep, but our thoughts are unconscious – rather like the perceptions we have without noticing them. I leave the reader to referee the discussion, but its unsatisfactory nature offers another reason why most philosophers have shied away from sleep.

Prof. Raymond Tallis 2012

Raymond Tallis is a physician, philosopher, poet, broadcaster and novelist. His latest book In Defence of Wonder is just out from Acumen

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