‘I write’, explains McGahern, ‘because I need to write. I write to see’. Writing is not, then, about bringing pleasure either to himself or to others. It is an activity drawn from need, an instinctual act. Nor is writing something entirely rational. There comes a time in the composition of any of his works when McGahern has to ‘trust to instinct and strong feeling and imagination’. But what is instinct? It is one of those words we tend to use rather lazily to explain away the inexplicable. How do swallows know the way back from southern Africa to that one Irish byre or barn in which they were born? Instinct, we say. But what is that? As Peter White, the eponymous pornographer's doctor friend in McGahern's fourth published novel declares, ‘If you can tell where instinct ends and consciousness begins you'll make us all our fortunes’. The question of what instinct might be fascinated W. B. Y eats, and he examines its nature in a 1917 essay on what he called ‘Anima Mundi’, the storehouse of images which is ‘scarce separable from what we have begun to call “the subconscious”’.