3. But since a rational animal not only has within itself these natural movements, but has moreover, to a greater extent than other animals, the power of reason, by which it can judge and determine regarding natural movements, and disapprove and reject some, while approving and adopting others, so by the judgment of this reason may the movements of men be governed and directed towards a commendable life. And from this it follows that, since the nature of this reason which is in man has within itself the power of distinguishing between good and evil, and while distinguishing possesses the faculty of selecting what it has approved, it may justly be deemed worthy of praise in choosing what is good, and deserving of censure in following that which is base or wicked. This indeed must by no means escape our notice, that in some dumb animals there is found a more regular movement than in others, as in hunting-dogs or war-horses, so that they may appear to some to be moved by a kind of rational sense. But we must believe this to be the result not so much of reason as of some natural instinct, largely bestowed for purposes of that kind. Now, as we had begun to remark, seeing that such is the nature of a rational animal, some things may happen to us human beings from without; and these, coming in contact with our sense of sight, or hearing, or any other of our senses, may incite and arouse us to good movements, or the contrary; and seeing they come to us from an external source, it is not within our own power to prevent their coming. But to determine and approve what use we ought to make of those things which thus happen, is the duty of no other than of that reason within us, i.e. of our own judgment; by the decision of which reason we use the incitement, which comes to us from without for that purpose, which reason approves, our natural movements being determined by its authority either to good actions or the reverse.