On November 4, 1825 in Paris the 25-year-old maid Henriette Cornier went to buy cheese from the shop of Mme Belon. Henriette was fond of Belon’s nineteen-month-old daughter Fanny, and persuaded her mother to let her take Fanny home to dress her. ‘Returning with speed to the house, [Cornier] went into the kitchen and took a large knife, which she carried with the child up to her chamber on the first floor. There she lay the child across a bed upon her back. She then with one hand seized the head, which hung over the bedstead, and with the other severed the head from the body with so much promptitude that the little victim had not time to utter one cry. The body remained on the bed, and the head she put into a cupboard. The blood flowed from the body, and she placed a vase on the floor to catch it.’

‘Two hours later the mother called for her daughter. From the top of the stairs, Henriette shouted, “She is dead,” and threw the head into the street. Questioned soon after, covered with blood, she answered apathetically, first, “C’est une idee qui m’a pris!” (The idea came to me!), and then, “J’ai voulu la tuer” (I intended to kill her).’

This murder, and others around the same time, came to matter because the psychiatric profession used them to argue, successfully, for broadening the notion of insanity. Criminal or ‘moral’ insanity came to apply to criminals who showed no previous signs of it. According to Foucault, ‘[i]t was stressed in each case that there was no previous history, no earlier disturbance in thought or behaviour, no delirium; neither was there any agitation, nor any visible disorder.’ Henceforth one could call the killer insane if the killing had no motive.

Cui bono? Well, over the next two centuries the psychiatrist would become as respected a courtroom figure as the pathologist or the ballistics expert. And by extending the criteria for diagnosis and hence the realm of treatment, the ‘science of the mind’ extended its sphere of control.

But there is something philosophically puzzling about how it could have happened at all. Imagine gastro-enterologists trying to expand their market by broadening the notion of a tummy-bug. They argue that besides typical symptoms of an upset stomach – complaints about it, frequent visits to the bathroom etc. – the following now also count as evidence: difficulty sleeping, difficulty waking up, sneezing, shortness of breath. At a stroke they, and the makers of indigestion-tablets, have doubled or tripled their clientele. Nice work if you can get it! 

Of course the tummy doctors never could get it, not like that; but somehow the mind doctors did. How they did is a complex story. A bit of it belongs to philosophy of mind; and on that bit the most dazzling light has been cast, not by Foucault, or by Charcot, but by the Austrian philosopher Ludwig Wittgenstein, via his idea of a family resemblance concept.

Philosophers have forever been asking things like: what is virtue? Or knowledge, or justice? Because presumably there is one thing, an essence of virtue (or knowledge, or justice) common to virtuous acts but absent from all vicious ones. Or how could we tell what virtue is?

But Wittgenstein attacks this presumption of essence with an example that is so familiar and straightforward that everyone sees the point at once. He writes:

‘Consider for example the proceedings that we call ‘games’. I mean board-games, card-games, ball-games, Olympic games, and so on. What is common to them all?—Don’t say: “There must be something common, or they would not be called ‘games’”—but look and see whether there is anything common to all.—For if you look at them you will not see something that is common to all, but similarities, relationships, and a whole series of them at that.’

There is no ‘essence of game’ distinguishing games from everything else, but a pattern of different similarities; just as some members of a family resemble in gait, others in expressions and others in manner of speaking. But nobody has any trouble understanding this ‘family resemblance’ concept.

Now the same goes, Wittgenstein thinks, for mental criteria: for belief, remembering, hope; also rage, depression and insanity. No one thing unifies behaviours expressing grief, or meaning something, or following a rule. The criteria for each form a family of behaviours resembling in different ways. 

Or consider the criteria for depression in the Diagnostic and Statistical Manual of Mental Disorders, the authority for psychiatric diagnosis. They include: depressed mood, energy loss, significant weight loss (or ‘decrease or increase of appetite nearly every day’.) No common feature distinguishes these features, and the other five, from criteria for other mental disorders; and determining whether the criteria are themselves satisfied is neither an easy business nor a precise one.

But surely, you might protest, depression is an inner process or state, one that either appears or doesn’t? Big mistake. Various processes in the brain might cause the various types of behaviour that we lump together as ‘signs of depression’; but these processes may be no more unified than the types of behaviour they produce. Paraphrasing what Wittgenstein says about another mental phenomenon (meaning), so as to cover this one:

[W]e do here what we do in a host of similar cases: because we cannot specify any one [type of behaviour] which we call [depression], we say that [a single] spiritual (mental, intellectual) activity corresponds to these words. Where our language suggests a body and there is none: there, we should like to say, is a spirit.

But our having a single word for something (‘depression’, ‘insanity’), it doesn’t follow that it means a single type of thing. On the contrary, these words collect various behaviours (or various brain processes) in ways that to earlier ages might have seemed – and could one day seem again – quite arbitrary.

And now we see how insanity differs from indigestion. The former – unlike the latter – has no fixed conceptual centre of gravity. The criteria for indigestion count as such via their connection with an inner gastric process. But there may be no inner brain process whose connection with (say) insomnia makes the latter a criterion of depression. That is why insanity is a more plastic concept; and how a wider range of behaviour came to be seen as a psychiatric problem to be identified and treated by psychiatric experts.

But Wittgenstein’s treatment of this subject is not only an explanation; it is also a warning. It reveals as an illusion any idea that ‘facts’ about the mind could prevent further conceptual changes that we might find less welcome.

Soviet psychiatrists broadened the notion of mental illness to include a new form of ‘sluggish’ schizophrenia. ‘Symptoms… included conflict with authorities, poor social adaptation and pessimism, and [these] were themselves sufficient for a formal diagnosis.’ In the 1970s this became a reason to lock up critics of the state in psychiatric wards.

And are we sure that no milder versions of these shifts impact our lives today? Who really benefits from the idea that aggression, or a fondness for drink, or introversion, or a tendency to systematise everything, are mental disorders? Is it the possessors of those traits? Is it ‘society’? Or is it the drug companies?

Tomas Szasz once wrote that the medicalisation of mental traits ‘is neither medicine nor science; it is a semantic-social strategy that benefits some persons and harms others.’ Wittgenstein revealed the semantic underpinning of the strategy; but the responsibility to identify it, and if necessary to fight it, will always rest with us.