From Miguel de Unamuno's Tragic Sense of Life:
"It is not usually our ideas that make us optimists or pessimists, but it is our optimism or our pessimism, of physiological or perhaps pathological origin, as much the one as the other, that makes our ideas.
Man is said to be a reasoning animal. I do not know why he has not been defined as an affective or feeling animal. Perhaps that which differentiates him from other animals is feeling rather than reason. More often I have seen a cat reason than laugh or weep."