What does Lacan show us? He shows us that desire is not a biological function; that it is not correlated with a natural object; and that its object is fantasized. Because of this, desire is extravagant. It cannot be grasped by those who might try to master it. It plays tricks on them. Yet if it is not recognized, it produces symptoms. In psychoanalysis, the goal is to interpret-that is, to read-the message regarding desire that is harbored within the symptom. Although desire upsets us, it also inspires us to invent artifices that can serve us as a compass. An animal species has a single...