Natural signs are those which, apart from any intention or
CHAP. II.] THE KINDS OF SIGNS. 35 know that there is fire beneath ; and when we hear the voice of a living man, we think of the feeling in his mind ; and when the trumpet sounds, soldiers know that they are to advance or retreat, or do whatever else the state of the battle requires.
2. Now some signs are natural, others conventional. Natural signs are those which, apart from any intention or desire of using them as signs, do yet lead to the knowledge of something else, as, for example, smoke when it indicates fire. For it is not from any intention of making it a sign that it is so, but through attention to experience we come to know that fire is beneath, even when nothing but smoke can be seen. And the footprint of an animal passing by belongs to this class of signs. And the countenance of an angry or sorrowful man indicates the feeling in his mind, independently of his will: and in the same way every other emotion of the ^ind is betrayed by the tell-tale countenance, even though we do nothing with the intention of making it known. This class of signs, however, it is no part of my design to discuss at present. But as it comes under this division of the subject, I could not altogether pass it over. It will be enough to have noticed it thus far.
Chap. ii.—Of the hind of signs we are now concerned with.
3. Conventional sims, on the other hand, are those which living beings mutually exchange for the purpose of showing, as well as they can, the feelings of their minds, or their perceptions, or their thoughts. Nor is there any reason for giving a sign except the desire of drawing forth and conveying into another's mind what the Q,iver of the sim has in his own mind. We wish, then, to consider and discuss this class of signs so far as men are concerned with it, because even the signs which have been given us of God, and which are contained in the Holy Scriptures, were made known to us through men—those, namely, who wrote the Scriptures. The beasts, too, have certain signs among themselves by which they make known the desires in their mind. For when the poultry-cock has discovered food, he signals with his voice for the hen to run to him, and the dove by cooing calls his mate, or is called by her in turn ; and many signs of the same kind are matters of common observ^ation. Now whether these signs, like the