intermixed with facts derived from travellers. Yet we believe in the invasion without the slightest hesitation. Cæsar, we say, would not have told the lie; or, if he had, it would have been quickly exposed by his enemies. In other words, we believe in the truth of the narrative, because a belief in its falsehood does not "work," that is to say, does not suit with what we know (or, more properly, with what others know) of Cæsar's character and Cæsar's times. Of precisely the same kind is almost all our knowledge about history: it is based upon evidence, but it is belief; and the only test of its truth is, does it "work," i.e. does it fit in with other knowledge which we regard as established truth?
But you see that, even in dealing with a simple action of Cæsar's, we have already drifted into a reference to Cæsar's motives: and obviously knowledge about "motives" is an important and indeed a paramount element in knowledge about persons. "My father," says the child, "has his brows knit; his face looks dark; he speaks very loud; his eyes look brighter than usual:"—this is knowledge about actions derived from personal observation, but, so far, perfectly useless, until something is added to it. "Whenever my father has looked and spoken like this before, he has been angry and has punished somebody: therefore he is angry and will punish somebody now"—this is not knowledge, it is only belief; but it is belief not about actions simply, but about motives as well as actions, and it may be of the greatest use.
How do we gain knowledge about motives, the moving powers of the human machine? Since we cannot take this machinery to pieces, or experiment with it freely, we must derive our knowledge largely from the consciousness of our own motives. Tickling produces laughter in us, and pricking, a cry; affection, and the command of those whom we love, produce in us obedience; desire of a result
