“When a depressed person does get out of bed, it’s usually not with a sudden insight that life is rich and valuable, but out of some creeping sense of duty or instinct for survival. If collapsing is sometimes vital, so is the brute force of will. To William James we owe the insight that, in the absence of real health, we sometimes must act as if we are healthy. Buoyed by such discipline and habit, we might achieve actual well-being.”