Whether he was acting ill or well he did not know, and far from laying down the law about it, he now avoided talking or thinking about it. Thinking about it led him into doubts and prevented him from seeing what he should and should not do. But when he did not think, but just lived, he unceasingly felt in his soul the presence of an infallible judge deciding which of two actions was the better and which the worse; and as soon as he did what he should not have done he immediately felt this. In this way he lived, not knowing or seeing any possibility of knowing what he was or why he lived in the world.
Leo Tolstoy, Anna Karenina
doubt, self-knowledge