If the behaviour of babies and small children is any guide, we emerge into the world with our tendencies to imbalance already well entrenched. In our playpens and high chairs, we are rarely far from displaying either hysterical happiness or savage disappointment, love or rage, mania or exhaustion--and, despite the growth of a more temperate exterior in adulthood, we seldom succeed in laying claim to lasting equilibrium, traversing our lives like stubbornly listing ships on choppy seas.