Why this is so, may be shown by a reference to the operation of Nature in other ways. The rewards of physical strength and health are not given to the most moral, to the most humane, to the most gentle, but to those who have acted, and whose forefathers have acted, in the most perfect accordance with the laws of their physical constitution. So the perfection of the intellectual life is not given to the most humble, the most believing, the most obedient, but to those who use their minds according to the most purely intellectual methods. One of the most important truths that human beings can know is the perfectly independent working of the natural laws: one of the best practical conclusions to be drawn from the observation of Nature is that in the conduct of our own understandings we should use a like independence. It would be wrong, in writing to you on subjects so important as these, to shrink from handling the real difficulties. Every one now is aware that science must and will pursue her own methods and work according to her own laws, without concerning herself with the most authoritative affirmations from without. But if science said one thing and authoritative tradition said another, no perfectly ingenuous person could rest contented until he had either reconciled the two or decidedly rejected one of them. It is impossible for a mind which is honest towards itself to admit that a proposition is true and false at the same time, true in science and false in theology. Therefore, although the intellectual methods are entirely independent of tradition, it may easily happen that the indirect results of our following those methods may be the overthrow of some dogma which has for many generations been considered indispensable to man's spiritual welfare. With regard to this contingency it need only be observed that the intellectual forces of humanity must act, like floods and winds, according to their own laws; and that if they cast down any edifice too weak to resist them, it must be because the original constructors had not built it substantially, or because those placed in charge of it had neglected to keep it in repair. This is their business, not ours. Our work is simply to ascertain truth by our own independent methods, alike without hostility to any persons claiming authority, and without deference to them. FOOTNOTES: [6] The title of this letter seems so odd, that it may be necessary to inform the reader that it was addressed to a real person.