How, then, and in what manner should they receive such training? Since it so happens that the human being is not soul alone, nor body alone, but a kind of synthesis of the two, the person in training must take care of both, the better part, the soul, more zealously; as is fitting, but also of the other, if he shall not be found lacking in any part that constitutes man. For obviously the philosopher's body should be well prepared for physical activity, because often the virtues make use of this as a necessary instrument for the affairs of life. Now there are two kinds of training, one which is appropriate for the soul alone, and the other which is common to both soul and body. We use the training common to both when we discipline ourselves to cold, heat, thirst, hunger, meager rations, hard beds, avoidance of pleasures, and patience under suffering.