In Latin, a lucus is a “dark grove”. In the eighteenth century, British etymologists decided that the word lucus came from the root verb lucere, meaning “to shine”. The idea was that a lucus was called a lucus because there was no lucendo going on there. The fact that this explanation achieved currency among schoolmasters gives you some sort of idea of the desperate state of Classical scholarship in Britain in the eighteenth century, by way of an introductory toccata to a short but ill-tempered discussion on another field in which truly terrible explanations are par for the course; Evolutionary Psychology. People who have read Henry’s comments in the same area are excused this one.
The trouble with lucus a non lucendo type explanations is that having learned one of them doesn’t help you at all with deducing any others. For example, if there were a particular type of mushroom that usually grew in dark groves, then the principle which led you to establish lucere as the root of lucus might start you thinking that it should probably be called a cuniculus, since rabbits don’t eat it. Or a vinum, because it doesn’t taste of wine. Or a catapult, because it isn’t one. Because the “non lucendo” explanation didn’t really add anything to our understanding of why a grove is called lucus, it doesn’t help you move on. There’s a general principle at work here, related to the parsimony of hypotheses; if something’s going to count as an explanation of X, then it ought to at least partly work as an explanation of things which are similar to X.
A number of explanations in evolutionary psychology don’t do very well by this criterion. Most glaringly, the famous “Natural History of Rape” by Randy Thornhill and Craig Palmer, which goes on for several hundred pages explaining how rape is either “an adaptation that was directly favored by selection because it increased male reproductive success by way of increasing mate number” or “a product of other psychological adaptations, especially those that function to produce the sexual desires of males for multiple partners without commitment”. This is a pretty controversial theory in and of itself, but let’s pretend that we all took it on board as a really good theory of why men commit rapes. How far does this get us as a theory of things similar to rape?
Well, what’s similar to rape? Two things; consensual sex is similar to rape in that it involves sex. And aggravated sexual battery is similar to rape in that it’s a sexual assault. Thornhill and Palmer’s theory (that rape is either a mating strategy or a byproduct of mating strategies) works reasonably well in giving us a theory of consensual sex – that’s also likely to be a mating strategy. But not very well at all in giving us a theory of aggravated sexual battery. Or indeed of any other sex crime which does not involve the vaginal penetration of a woman of childbearing age. It’s an explanation that doesn’t explain.
And similarly with the Sad Hominid explanation of depression (that under stress, some people become depressed, which helps their reproductive chances because it means that people will feel sorry for them and look after them). Ignoring the physiological implausibility of this explanation (clinical depression is often associated with erectile dysfunction in men, and you’re gonna have to work hard to convince me that impotence is a good way of maximising one’s progeny), it fails by the lucus a non lucendo criterion as well. Some people under stress end up with depression. However other people develop different mental illnesses, most of which render them much less sympathetic than the stereotypical depression patient. It’s hard to see this theory of depression working well as a theory of paranoid behaviour or of schizophrenia. Which is odd, as cases of depression are often found alongside cases of one of these other serious mental disorders.
Part of the issue here is that any form of psychology makes a poor sociology, and it’s only evolutionary psychology that tries to pretend that the distinction between individual and social psychology doesn’t exist.
[The reason for this, by the way, is that “evolutionary psychology” is simply a rebranding exercise for sociobiology. It’s not extending proven psychological results forward into the social sphere. It’s building backward into a “hard” science in order to shore up already constructed sociological theories which have come under attack. As a method of scientific inquiry, this has all the merits of constructing a house roof first and foundations last.]
And the other part of the issue is that, however much Steven Pinker would like it to be, the mind is not a Swiss Army knife and the division of psychological entities into modules is something without anatomical basis when carried out at the level of anything other than the broadest and most general ur
behaviours. The only things which are even a candidate for evolutionary explanation are the big drives; eating, reproduction, childcare, status, suppression of samespecies aggression. And these are the things in which nobody has ever disputed the role of evolution. The fact that a) we have a sex drive and b) the existence of this sex drive is explained by our Darwinian imperative toward reproduction was there in Freud for chrissakes. And the fact that the simple existence of a sex drive is next to useless in explaining any specific human sexual behaviour has been known since very shortly after Freud. It’s the same with all our broad drives. Almost everything we do in an average day is just simply too complicated and specific to a particular time and place to be the subject of any evolved module (or to be the subject of any general reasoning at all, as Hayek pointed out).
So when one feels tempted to compromise with the evolutionary psychologists, and to say that “perhaps Darwinian evolutionary theory can shine some light on this social conundrum”, it’s worth remembering that this light is highly likely to be a lucus a non lucendo. Vale.
An entirely unfair remark on my part; the original source of the “lucus a non lucendo” etymology was Marcus Honoratus in the fourth century AD and the majority of serious British classicists correctly deduced that he was joking. But it was in the C18 that the error became popular.
Or possibly Marcus Terentius Varro in the second century BC. Or possibly Virgil.
By the way, I was never taught this crap, I just pick it up off Google.