The last two books of the Ethics, entitled respectively “Of human bondage, or the strength of the emotions” and “Of the power of the understanding, or of human freedom,” are the most interesting. We are in bondage in proportion as what happens to us is determined by outside causes, and we are free in proportion as we are self-determined. Spinoza, like Socrates and Plato, believes that all wrong action is due to intellectual error: the man who adequately understands his own circumstances will act wisely, and will even be happy in the face of what to another would be misfortune.