In this section Spinoza discusses man’s “bondage” to the affects, which exercise a power over man that he must escape if he is to be free and happy.

Spinoza starts with a metaphysical discussion. He argues that natural things cannot be called “perfect” or “imperfect” because everything in nature is determined and necessary. All things follow from the existence of God, and God does not exist for the sake of any end. Therefore, things in nature do not happen for any end—certainly they do not happen to benefit us—but flow necessarily from the nature of God. Thus, perfection and imperfection are not inherent realities but only useful “modes of thinking” (115).

This leads Spinoza to stake an important claim: Good and bad, or good and evil, are not inherent in things but are only ways of thinking about reality. “Good” simply means “what we certainly know to be useful to us,” and evil means “what we certainly know prevents us from being masters of some good” (116). Appetite, then, is “the end for the sake of which we do something” (117). Virtue means man’s power of bringing about certain things and “acting from the laws of one’s own nature” (125). The things we call good and evil are things that enhance or diminish our power.