Plato offers a more intuitive explanation for why the philosopher is virtuous. Since all of him strives toward truth, his other desires are weakened. He has no real drive toward money, honor, pleasure, and so on. In short, he has none of the drives that can lead to immoral behavior. He would never be motivated to steal, lie, boast, act slavishly, or anything else of this sort. His emotions and appetites no longer provide a strong impetus toward vice.
Posted by Paul Hunter