You will see better what I mean if you consider this analogy: suppose one of these daring poets were to say that there was once a man with three heads and six hands, and suppose that you facilely accepted this without asking if it were possible, just believing, he would at once follow it up by filling in the details appropriately—six eyes, six ears, three voices coming from three mouths, each taking food, and thirty fingers, unlike us with our ten on two hands; and, if he had to go to war, three hands held three shields—light, oblong, or round—, and three brandished axe, spear, and sword. Who would disbelieve these details now—details which are consistent with the first outline? It was there that you ought to have seen whether it was credible or acceptable thus. Once you admit the premises the rest comes flooding in; you will never stay its course, and disbelief is difficult now, for what follows is consistent in the way it follows the agreed premises. This has happened to you all. Because of your love and enthusiasm you made no enquiry into the conditions at each entrance. You go forward led by the consistency of what came after, not considering that things may be consistent and false. Suppose for instance you were to believe someone who said that twice five is seven and did not count for yourself, he will clearly go on to say that four times five is certainly fourteen, and so on, as long as he likes. This is what that marvellous geometry does—in the beginning it presents certain monstrous postulates and demands that we consent to them though they cannot exist—for instance points without parts, lines without breadth, and so on—and on these rotten foundations it erects its structure and claims to demonstrate truths, in spite of the fact that it starts from a false beginning.