XIX. (109) For this reason all animals with solid hoofs, and all with many toes are spoken of by implication as unclean; the one because, being so, they imply that the nature of good and evil is one and the same; which is just as if one were to say that the nature of a concave and a convex surface, or of a road up hill and down hill, was the same. And the other, because it shows that there are many roads, though, indeed, they have no right to be called roads at all, which lead the life of man to deceit; for it is not easy among a variety of paths to choose that which is the most desirable and the most excellent.


XX. (110) Having laid down these definitions with respect to land animals, he proceeds to describe what aquatic creatures are clean and lawful to be used for food; distinguishing them also by two characteristics as having fins or Scales.{21}{#le 11:9.} For those which have neither one nor the other, and those which have only one of the two, he rejects and Prohibits.{22}{#de 14:10.} And he must state the cause, which is not destitute of sense and propriety; (111) for all those creatures which are destitute of both, or even of one of the two, are sucked down by the current, not being able to resist the force of the stream; but those which have both these characteristics can stem the water, and oppose it in front, and strive against it as against an adversary, and struggle with invincible good will and courage, so that if they are pushed they push in their turn; and if they are pursued they turn upon their foe and pursue it in their turn, making themselves broad roads in a pathless district, so as to have an easy passage to and fro. (112) Now both these things are symbols; the former of a soul devoted to pleasure, and the latter of one which loves perseverance and temperance. For the road which leads to pleasure is a down-hill one and very easy, being rather an absorbing gulf than a path. But the path which leads to temperance is up hill and laborious, but above all other roads advantageous. And the one leads men downwards, and prevents those who travel by it from retracing their steps until they have arrived at the very lowest bottom, but the other leads to heaven; making those who do not weary before they reach it immortal, if they are only able to endure its rugged and difficult ascent.