Socrates continually returned to the question that if you wanted to make your horse a good horse, you would know where to send them, and if you wanted to make your son a good doctor (i.e. a skilled one), you would have a decent idea of where to send him; so where do you send your son to make him a good man? Where could you even send yourself to learn this?
One approach to the question is to say that we know how to make good horses, dogs and doctors because all these things are natures as opposed to persons. There is no name for an individual substance of a canine, equine or medically competent nature because there is no ontological reality that is separate from the individuated nature. A dog or a horse or a doctor all have personal names, but there is nothing that corresponds to what the word person is to human nature. A nature is common, undifferentiated, and universal, and so what has no ontological reality beyond its nature can be perfected by a system that deals with what is common, undifferentiated, and universal. An obedience school, equestrian center, or medical school can all bring a nature to completion, but the question of what makes for a good man adds an additional, separate ontological component to this: the person. A process making a good horse can, within limits, disregard what is unique and peculiar to any given horse, but the process of becoming a good man cannot disregard the concrete individual. The process of making a good man cannot be an impersonal and anonymous process. A no- nonsense medical school might well make doctors by simply conveying information and drilling in practice, and without ever treating any of the students as persons, but a school that sought to make its students mature moral persons but which never treated them as persons would be a pretty creepy joke. Information and drilling suffice only when addressed to the nature – the person needs something in addition to this.
Moral education must treat of the person in addition to the nature, and so new sorts of things become significant: the perfection of a man requires some perfection of his heart, that is, the dynamic center of an individual that is personally committed to things, and who cannot simply execute actions but must be engaged and involved with them.
It was Christianity that forced us to see the division between nature and person – unless person is an ontologically separate reality from nature (i.e. if a person is nothing but an non-universal human nature) the orthodox account of Christ becomes impossible. Nevertheless, we have yet to get much beyond seeing that this is so. Martin Buber seems to have been one of the first to begin to work out some of the initial implications of this division, and the critique of Naturalism seems to point towards making a sharper distinction between the person and nature though the division of the first person/subjective and the third person/ scientific.