22. You err, my opponent says, and are deceived; for the gods are not themselves artificers, but suggest these arts to ingenious men, and teach mortals what they should know, that their mode of life may be more civilized. But he who gives any instruction to the ignorant and unwilling, and strives to make him intelligently expert in some kind of work, must himself first know that which he sets the other to practise. For no one can be capable of teaching a science without knowing the rules of that which he teaches, and having grasped its method most thoroughly. The gods are, then, the first artificers; whether because they inform the minds of men with knowledge, as you say yourselves, or because, being immortal and unbegotten, they surpass the whole race of earth by their length of life. ^[3982] This, then, is the question; there being no occasion for these arts among the gods, neither their necessities nor nature requiring in them any ingenuity or mechanical skill, why you should say that they are skilled, ^[3983] one in one craft, another in another, and that individuals are pre-eminently expert ^[3984] in particular departments in which they are distinguished by acquaintance with the several branches of science?