He tried to decide if he was really ashamed of being afraid, and decided that he was not. Fear was there for a purpose. It was wired into any creature that had not completely turned its back on its evolutionary inheritance and so remade itself in whatever image it coveted. The more sophisticated you became, the less you relied on fear and pain to keep you alive; you could afford to ignore them because you had other means of coping with the consequences if things went badly.
Iain M. Banks, Look to Windward
fear, fight-or-flight, human-nature, instinct