But despite the undoubted terror of holding certain beliefs, and the loneliness of being the only person you know who does, it would be hard to imagine anyone ever having them if there wasn't something about them that we sometimes needed.
And in fact we have become accustomed to thinking of delusions as a defence, that is as being at least preferable to something worse. For Freud they were elaborate ways of getting away from homosexual longings. You start with a forbidden love, and how you go about denying it determines what sort of delusion you end up with. Freud accounted for delusions of persecution (”I do not love him I hate him” gets projected to “he hates me”), "Erotomania" (”I do not love him I love her”), delusions of jealousy ("it is not I who love the man, she loves the man") and megalomania ("I do not love at all-I don’t love anyone”). So systematic was Freud that his equation hung around for close to a century (and still holds sway in some quarters).
In a related vein, the philosopher Lisa Botolotti recently suggested that delusional beliefs could represent a sort of epistemic damage limitation. Better that you entertain a single false belief than suffer a broader psychic overwhelm and become unable to believe anything. This is the delusion as adaptive, as the fuse which can be allowed to blow in order to stop the whole edifice burning down. What these accounts all share is the suggestion that delusions are the least worst of several bad options. Put it that way and we focus on the unpleasantness of what is being defended against, but what about the appeal of holding a delusional belief? It begs the question of what role our everyday beliefs hold for us. Hang around delusions research for long enough and you start to ask why anyone believes anything.
This is what brings me to the question of pleasure. Think of how pleasurable it is when you know the answer and no-one else does, when you finally figure it out, when everything suddenly makes sense. Addressing herself to the difficult question of what constitutes a satisfactory explanation, psychologist Alison Gopnik described "explanation as orgasm". Think, she suggests, of the way children (those "little scientists") seek endlessly for explanations, would they really be doing that if it wasn't a lot of fun? Richard Feynman spoke about "The pleasure of finding things out". As a research physicist, Feynman really was in the process of "finding things out", but don't the rest of us get pleasure from thinking we understand things better than we do? Anyone who has spent time in a bar with some politically disgruntled bore will recognise the peculiar glee that accompanies the "conspiratorial whisper". It is the pleasure of seeing through it all; of knowing what other people don't know. Might delusions sometimes afford something of that pleasure?