<p> This study traces a persistent connection between the image of disease and the concept of difference in Plato&rsquo;s <i>Gorgias, Phaedo</i>, and <i>Timaeus</i>. Whether the disease occurs in the body, soul, city, or cosmos, it always signals an unassimilated difference that is critical to the argument. I argue that Plato represents&mdash;and induces&mdash;diseases of difference in order to produce philosophers, skilled in the art of differentiation. Because his dialogues intensify rather than cure difference, his philosophy is better characterized as a &ldquo;higher pathology&rdquo; than a form of therapy. </p><p> An introductory section on <i>Sophist</i> lays out the main features of the concept of difference-in-itself and concisely presents its connection to disease. The main chapters examine the relationship in different realms. In the first chapter, the problem is moral and political: in the <i> Gorgias</i>, rhetoric is a corrupting force, while philosophy purifies the city and soul by drawing distinctions. In the second chapter on <i> Phaedo</i>, the problem is epistemological: if we correctly interpret the illness of misology, as the despair caused by the inability to consistently distinguish truth and falsity, we can resolve the mystery of Socrates&rsquo; cryptic last words (&ldquo;We owe a cock to Asclepius; pay the debt and do not neglect it&rdquo;). In the third chapter on <i>Timaeus</i>, Plato treats diseases of the soul, the body, and the cosmos itself. There, the correlation between disease and difference actually helps humans situate themselves in the vast universe&mdash;for in both cases, proper differentiation is the key to a healthy, well-constructed life. </p><p> My emphasis on Plato&rsquo;s theory of difference counters the traditional focus on his theory of Forms. Elucidating the link between the concept of difference and the experience of disease has broader impact for the ageless question of how we should live our lives. In Plato&rsquo;s system, neither disease nor difference is a wholly negative element to be eradicated. Instead, difference and disease, in their proper proportions, are responsible for the fullness of the world and the emergence of the philosophical subject.</p><p>