Vitality and Virtue

There is no singular work by Aristotle on health, yet the term is used across many of his texts. From biology, to ethics, to physics and metaphysics health is mentioned and used throughout the texts to explain his concepts. Likewise, for all the elenchus and aporia we read in the Platonic dialogues, it is curious that health is never questioned. In fact, we find that many of the dialogues rely on health as the figure to understand virtue, courage, piety and even beauty itself. It would seem to know health is a prerequisite to know anything, for Plato.