"The Therapy of Desire" is without doubt one of the best written, most erudite, and exhaustive studies of Hellenistic practical philosophy available, beginning with Plato and concluding with the Stoics. Nussbaum's focus, however, is not all the philosophical concepts touched upon during this enormous stretch of time, but with human flourishing (i.e., eudaimonia) and the important ethical insights of this period. Using the medical paradigm that the philosophers themselves used, she approaches Aristotle, the Epicureans, the Skeptics, and finally the Stoics conception of the good life well lived. Each of these philosophical schools attempted to "treat" the disorders of the mind (i.e., psyche), particularly the emotions and how they divert the soul from health to disease.
She begins with Plato's and Aristotle's belief that the emotions are a "part" of the soul, separate and distinct from the ratiocinative part. Plato thought all emotions needed to be controlled by reason (the charioteer and the two steeds), while Aristotle thought the emotions, distinct from the appetites and reason, need to find the golden mean through the process of using the intellect to control the passions from excess or deficiency. The Epicureans, on the other hand, make no such distinction, arguing instead that all emotions are flawed if they don't have the right premises (usually the "universal" premise) of practical thinking. Change the universal premise, usually by rote memory of rules of inference, and the emotions are tamed. The Skeptics took the approach that all passionate and deliberative thought was premised on false premises; citing Sextus Empiricus and his extreme Pyrrhonism, she illustrates how their resistance to all forms of dogmatism, e.g., certainty about the truth in any form, was a ruse. (I think Nussbaum could have explored the Skeptics more thoroughly than she does.) The Skeptics insisted that no two people perceive the same thing in the same way; even emotional responses were entirely unique and based upon the "belief" that something was true, when in fact, no belief is true. Their approach was simply to "suspend" all judgments altogether, thereby not being committed to one way of thinking or another.
The Stoics, on the other hand, alight onto something Nussbaum finds both intriguing and true. The emotions are not a separate faculty of the soul, but the same faculty involved in ratiocination. Emotions are nothing more than "internal" cognitive reactions to external stimuli. Treatment of the soul, for the Stoics, was apathy (i.e., ataraxia): Don't let the soul (i.e., mind) become "disturbed" by external factors. By simply extirpating emotive reactions, the Stoic "therapy" involves the complete the annihilation of the emotions altogether. External (cf., internal) conditions are simply a matter of fate or whim, neither within nor without one's control. Why get exercised over them? It only begets anger, frustration, and depression. Only our internal reaction to them are controllable. The only way to deal with our reactions is to ignore or repress them, or else they will take control over the self -- and almost always for the worse. Anger, fear, frustration, anxiety, love,pity,compassion,grandiosity, our finitude, etc., do not come form the outside; they are emotions that cognitively react to outside events beyond the self's control. But what good do they serve? None. They only make one react to things that are outside the agent's control. The tonic: Overcome them through extirpation, and thus lead a calm, dispassionate, and equipoised life.
Nussbaum's erudite, sophisticated, and elegant evaluation of these schools of thought ought to engender the person of the twenty-first century into "current" modalities for the treatment of mental disorders. In the "Therapy of Desire" she lays the intellectual and historical foundations of current cognitive modalities. (This she explores in greater detail into her sequel "Upheavals of Thought.") But, by confining ourselves to this rich intellectual, hermeneutic, and "medical" history of the Hellenistic period, we can already anticipate the use of both Epicurean and Stoic thought in Cognitive Behavior and Rational-Emotive Behavior Therapies, and how successful both paradigms have become. (For example, see Elliot Cohen's "What Would Aristotle Do?" and Albert Ellis' "A Guide to Rational Living.") Nussbaum not only weaves a coherent, intelligent, and persuasive understanding of Hellenistic thought, she provides the ancient, and yet contemporary, underpinnings of modern cognitive psychology. Her book is rich in quotes from both periods, and is an excellent introduction into why the ancient Greek/Roman philosophers still speak to us today.