Page:Popular Science Monthly Volume 28.djvu/419

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Messrs. Editors:

I READ the first few pages of the Bishop of Carlisle's essay on the "Uniformity of Nature," in the last number of this magazine, with a lively expectation that some of the fog and uncertainty left hanging around the question by the debaters of the "Metaphysical Society" was to be cleared up. But all such expectation ended before I had finished the article. The fog and uncertainty became more bewildering than ever. In fact, it seems to me the worthy bishop missed the mark entirely. He set out to tell us what was meant by the uniformity of Nature, and arrived at the conclusion that, outside of celestial mechanics, it, in effect, meant simply unchangeableness of the weather, uniformity in the direction of the wind, invariableness in the form and density of bodies, etc., and was therefore a principle of only a very limited application.

How absurd, in the first place, to go back to ciphering out by Newton and Laplace of the problems of the laws and motions of the heavenly bodies, for the origin of the practically universal belief in the uniformity of Nature! You might as well go back to them for the origin of our practical belief in density, gravity, inertia, or in the existence of the sun and moon themselves. The whole course of our lives is predicated upon our faith in the uniformity of Nature, upon the belief that fire burns, that cold freezes, that gravity is always operative. Would a man ever plant seed in the ground if he did not believe the laws which govern its growth and development were constant? Have the laws (no matter how ignorant we are of them) which govern steam, which govern all fluids and solids and gases, which govern contraction and expansion and condensation, ever been known to fail? The moment any uncertainty is discovered here, our whole philosophy of mechanics is in ruins. Because the weather is changeable, does the bishop therefore think that the laws which govern the formation of clouds, which determine the course of the winds, and the precipitation of moisture in the shape of rain and snow, are not uniform; that, given the same conditions, the same results will not follow? Would he pray for rain, or for the rain to cease? Would he pray for the postponement of an eclipse? Or would he say that, because man has changed the face of the earth, he has not done it under the rigid operation of natural law? that he has reversed the law of gravity, the laws of heat and cold, of wet and dry, of the tides and the seasons? Is it not true, rather, that he has done it by strictly following and obeying these laws? A belief in the uniformity of Nature does not mean a belief in the uniformity of appearances or of phenomena. The law is not disproved because some of the worlds are large and some small, some hot and some cold, some dense and some thin; or because some animals have two legs and some four or six, some feathers and some hair, or because some crows are white and some swans black, or because some fruit has the seed upon the outside and some on the inside. But show us a country where the trees are walking about, and the men are rooted to the ground, and our belief in the uniformity of Nature will at least receive a severe shock. Would not the same conditions that produce a white crow or a white negro once always produce a white crow or a white negro? This, then, is what we mean and must mean by the uniformity of Nature, that, given the same conditions, the same results will always follow. If this truth does not hold good at all times and in all places, then, indeed, is "the pillared firmament based upon rottenness." A breach in the uniformity of Nature means a breach of this law. If ice should fail to melt in the fire, or if water should flow uphill, or lead swim where a feather would sink, then would the uniformity of Nature be disproved. If the Bishop of Carlisle, or any other person, will make an axe-head swim upon water, as Elisha did, and under the same conditions that would send the iron to the bottom at all other times, then must we either give up the belief in the uniformity of Nature, or else believe in the existence of a set of laws which may be brought to bear upon material bodies by the human will, so as to reverse or annul the laws by which they are ordinarily governed. And the existence of such laws and of such power of the human will is an assumption which no sane man can accept.

If the sun should fail to rise tomorrow, it would be no breach of the uniformity of Nature. If the sun failed to rise, could it be from other than physical or natural cause; from the operation of laws which are uniform in their workings? If we are to believe what astronomers tell us about the disappearance of certain stars, then the sun of some world or worlds has failed to rise on the morrow. Have given the same conditions, and would not our sun disappear also? No; facts of this kind can not be relied upon to invalidate the principle of