His glory, "Being what they are, my children must be led to knowledge through error, to truth through illusion"? It may be said that in some cases men have fallen into astronomical mistakes through their own fault; through haste, for example, through the love of neat and complete theories, through carelessness, through excessive regard for authority; and so indeed they have. But is it always so? When you and I last walked out together on Hampstead Heath, you took out your watch, as the sun went down over Harrow, and said, "Now he's gone, and it's just eight." I remember replying to you, "So it seems; but of course you know he 'went' more than eight minutes ago." You stared, and I said no more; for something else diverted your attention at the time, and I felt I had been guilty of a little bit of pedantry. But I said quietly to myself as we went down the hill, "I don't suppose he knows it, but the sun certainly 'went' eight minutes ago; and what my young friend saw was an image of the sun raised by the refraction of the mist, like the image of a penny seen in a basin of water." Well now, was this your fault, this error of yours? No, it was, in the second place, the fault of the University of Oxford, which has bribed the schools to desist from teaching mathematics to any boy with a taste for classics and literature, so that you had to give up your mathematical studies before you came to optics; and it was, in the first place, the fault of—what shall I say? Shall I say the fault of Nature? That means the fault of God. Say, if you like, that it was the fault of Matter, or of an Evil principle. Say, it was no one's fault. Say that more good than harm results from it, in the way of stimulating thought and research. Deny it was a fault at all. Yet do not deny that it represents a Law, the Law of the attainment of truth through illusion—a Law which it is folly to ignore.
