Self remains my favourite short story writer. ‘The Quantity Theory of Insanity’ depicts an eccentric academic who invents the conceit that there is a fixed quota of insanity in the world, and therefore that “if you provide efficient medication for manic depressives in the Fens, there are perceptible variations in the number of agoraphobics on the South coast”. I think I was initially drawn to Self’s writing because he writes about madness so well. ‘Quantity’ – both the story and collection – captured the quiddity of my father’s illness (schizophrenia), far better than many stories/novels which aimed to portray the illness in a more direct and obvious fashion. It’s the tone of the story that resonated: the wonderful mixture of the banal and the bizarre, the comic and the tragic, and the swirling schizoidy colours of Self’s imagination. It’s also the first of Self’s stories, I believe, that introduces Dr Busner, the Laingian psychiatrist who became a recurrent figure in Self’s fiction.
First published in The Quantity Theory of Insanity, Bloomsbury 1991