The problem of the worth of life is often regarded as one that the healthy have no wish to discuss, and the unhealthy no right to decide. However, reflective beings must sooner or later to consider the worth of conscious life; for self-criticism is an essential part of all mental growth. But as every new step in critical thought is made by means of a negative criticism of old positions, the question of the worth of life must distinctly appear for the first time in the form of what is inexactly called pessimistic doubt about human life. This chapter considers the doctrine popularly named pessimism, which believes that evil is on the whole triumphant. The ultimate aim of the discussion is to present some thoughts on the method of estimating the worth of human life.