impulse is the medium of emotion; the seed of all impulse is a feeling bursting to express itself in action. Those who are at the mercy of impulse--who lack self-control--suffer a moral deficiency: The ability to control impulse is the base of will and character. By the same token, the root of altruism lies in empathy, the ability to read emotions in others; lacking a sense of another's need or despair, there is no caring. And if there are any two moral stances that our times call for, they are precisely these, self-restraint and compassion.