The inventor of a brilliant idea cannot tell whether it is right or wrong. The psychologist Daniel Kahneman describes how theories are born: "We can't live in a state of perpetual doubt, so we make up the best story possible and we live as if the story were true." A theory that began as a wild guess ends as a firm belief. Humans need beliefs in order to live, and even the greatest of scientists are no exception. Great scientists produce right theories and wrong theories, and believe in them with equal conviction.
The passionate pursuit of wrong theories is part of the normal development of science. Science is not concerned only with things that we understand. The most exciting and creative parts of science are concerned with things that we are still struggling to understand. Wrong theories are not an impediment to the progress of science. They are a central part of the struggle.
