The third chapter of the book addresses a fundamental paradox of civilization: it is a tool we have created to protect ourselves from unhappiness, and yet it is our largest source of unhappiness. People become neurotic because they cannot tolerate the frustration which society imposes in the service of its cultural ideals. Freud points out that advances in science and technology have been, at best, a mixed blessing for human happiness. He asks what society is for if not to satisfy the pleasure principle, but concedes that as well as pursuing happiness, civilization must also compromise happiness in order to fulfill its primary goal of bringing individuals into peaceful relationship with one another, which it does by making them subject to a higher, communal authority. Civilization is built out of wish-fulfillments of the human ideals of control, beauty, hygiene, order, and especially for the exercise of humanity's highest intellectual functions. Freud draws a key analogy between the development of civilization and libidinal development in the individual, which allows Freud to speak of civilization in his own terms: there is anal eroticism that develops into a need for order and cleanliness, a sublimation of instincts into useful actions, alongside a more repressive renunciation of instinct. This final point Freud sees as the most important character of civilization, and if it is not compensated for, then “one can be certain that serious disorders will ensue.". The structure of civilization serves to circumvent the natural processes and feelings of human development and eroticism. It is no wonder then, that this repression could lead to discontent among civilians.