EMOTIONS are the stuff of life. Anger, shame, fear, joy and love are immensely powerful states of mind. Subjectively, they are experienced as overpowering. We do not choose to have them; rather, we are in their grip. Our strongest emotions keep us awake at night, loosen our bowels, lend supernatural acuity or deep gloom to our perception of the world and help us achieve wonders when they do not leave us paralyzed. Other emotions are more subtle, less violent, yet no less central to our life. Hope and surprise, disappointment and regret, wistfulness and longing, envy and malice, pride and contentment: these are the hues of everyday life. An affectively neutral experience, if we can envisage it at all, would be pointless. Creatures without emotions would have no reason for living, nor, for that matter, for committing suicide.

The importance of emotions in human life is matched only by the neglect they have suffered at the hands of philosophers and social scientists. The nature, causes and consequences of the emotions are among the least well understood aspects of human behavior, matched only by our poor understanding of social norms (chapter XII), to which they are closely linked. There has been more speculation about than careful attention to these phenomena. Emotions have been explained in terms of their alleged benefits for biological survival, social cohesion or personal advance, not studied in their immediate vividness.