The lure of death: suicide and human evolution

Humphrey N. 2018 The lure of death: suicide and human evolution. Phil. Trans. R. Soc. B 373: 20170269. http://dx.doi.org/10.1098/rstb.2017.0269

Suicide used to be called self-murder, felo de se. In an evolutionary context, the term murder is not inappropriate. Human beings have always been murderers, killers of other living beings. First, of course, killers of animal prey for meat, but also killers of other men and women. While not every ancient human would have had first-hand experience of assassination, everyone would have known and talked about it. Then, at some point, the idea must have dawned. Here’s how the psychiatrist, Erwin Stengel has put it: ‘At some stage of evolution man must have discovered that he can kill not only animals and fellow-men but also himself. It can be assumed that life has never since been the same to him’ [1, p. 37].

The purpose of this paper is to consider just how radically life changed. I argue that the human mind must have had to evolve to a critical level of sophistication before anyone could arrive at the idea that ‘I can kill myself’. However, from then on, suicide would never have been far from people’s thoughts. When times were hard, some individuals would have been bound to see death as an attractive option. Yet killing themselves would usually—if not always—have been a maladaptive act. I explore how this played out historically, and what remedies, if any, were available.

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But, now, to go deeper: when you think ‘I can kill myself’, who is this ‘self’ and what do you imagine will result from ‘killing’ it? Again, Stengel implies that early humans would have understood the inevitable consequences of self-killing from observing the killing of others. Bodily death, however caused, has effects that anyone can see and take on board. There’s the obvious bodily decay. But the most salient change is in the dead person’s role as an actor in the physical or social world. They will not be coming back. This is a fact of death that non-human animals with complex social lives can also understand up to a point. Frans de Waal describes how, when a group of chimpanzees in the Arnhem Zoo were shown a video film of the alpha-male, Nickie, who had died by drowning 2 years earlier, his erstwhile rivals panicked as if they had seen a ghost [2, p. 214]. By applying this to your own case, you would realize that you yourself once dead will no longer participate directly in the lives of others.

But we must go deeper still. For there is, of course, another meaning of ‘self’, and hence, the probability that self-killingwill have a still more significant result. When your body dies, what happens to your mind? Once you are no longer an actor in the public realm, can you no longer be a thinker or feeler in the private one? This is not of course something you or anyone else can discover from direct observation. But it is perhaps something you can deduce from circumstantial evidence. As a human, with a ‘theory of mind,’ you expect to be able to infer another person’s mental state from their outward behaviour. When, now, you observe that an individual’s body no longer behaves in any way at all—it neither acts spontaneously nor reacts to your probes—you have very good reason to suppose there is no longer anyone at home inside. True, absence of evidence is not entirely reliable as evidence of absence. But, in fact, you yourself have had plenty of direct experience of your own mind going absent at a time of pseudo-death. When you fall asleep, and your body becomes motionless and unresponsive, you know for a fact that your mind temporarily vanishes. You may remember how as a child you cried yourself to sleep and found blessed relief in the ensuing oblivion.