Book 2
3.9
And now, he continued, we have been initiated into a method of fighting, which, I observe, all men naturally understand, just as in the case of other creatures each understands some method of fighting which it has not learned from any other source than from instinct: for instance, the bull knows how to fight with his horns, the horse with his hoofs, the dog with his teeth, the boar with his tusks. And all know how to protect themselves, too, against that from which they most need protection, and that, too, though they have never gone to school to any teacher.
3.10
As for myself, I have understood from my very childhood how to protect the spot where I thought I was likely to receive a blow; and if I had nothing else I put out my hands to hinder as well as I could the one who was trying to hit me. And this I did not from having been taught to do so, but even though I was beaten for that very act of putting out my hands. Furthermore, even when I was a little fellow I used to seize a sword wherever I saw one, although, I declare, I had never learned, except from instinct, even how to take hold of a sword. At any rate, I used to do this, even though they tried to keep me from it—and certainly they did not teach me so to do—just as I was impelled by nature to do certain other things which my father and mother tried to keep me away from. And, by Zeus, I used to hack with a sword everything that I could without being caught at it. For this was not only instinctive, like walking and running, but I thought it was fun in addition to its being natural.