 What kind of ‘binding force’ does Plato attribute to ‘the Good’? His reticence about this concept, despite its centrality in his metaphysics and ethics, is largely responsible for the obscurity of his concepts of happiness and of what it is to lead a good life, except for the claim that individuals are best off if they ‘do their own thing’. The philosophers’ knowledge provides a solid basis for the good life of the entire community, as well as for that of the – perhaps uncomprehending – majority, because they benefit from the good order of the state. But what is ‘the Good’ that is responsible for the goodness of all other things? A lot of ink has been spilt over the following passage in Republic book VI, 509b: “Not only do the objects of knowledge owe their being known to the Good, but their being (ousia) is also due to it, although the Good is not being, but superior (epekeina) to it in rank and power.” The analogy with the sun’s maintenance of all that is alive suggests that the Good is the intelligent inner principle that determines the nature of every object that is capable of goodness, in the sense that these objects fulfill their respective functions in an appropriate way. Plato did not attempt to state how such a principle of goodness works in all things when he wrote the Republic. That he was thinking of an internal ‘binding force’ is indicated, however, in Book X, where Plato elucidates the ontological differences that exist, respectively, between the Forms as the products of a divine maker, their earthly copies, and the imitation of these copies by an artist (R. 596a ff.). According to Plato, in each case it is the use or function that determines what it is to be good, (601d): “Aren’t the virtue or excellence, the beauty and correctness of each manufactured item, living creature, and action related to nothing but the use (chreia) for which each is made or naturally adapted?” Given that he does not limit this account to instruments, but explicitly includes living things and human actions in it, he seems to have a specific criterion in mind for what constitutes each thing’s excellence. A similar thought is already expressed in Republic I (353a–e) when Socrates, in his refutation of Thrasymachus, employs the argument that the ability to fulfill one’s own task (ergon) well constitutes the excellence of each object. In the case of human beings, this means ‘doing well’; ‘doing well’, in turn, means ‘living well’, and ‘living well’, in turn, means ‘living happily’. The stringency of these inferences is far from obvious; but they show that Plato saw an intimate connection between the nature, the function, and the well-being of all things, including human beings.