Tópico: [inglês] Mark Twain contesta A. R. Wallace: "o mundo foi criado para o homem?"

[Buckaroo Banzai]

Breve resumo em português. Wallace, conhecido como co-descobridor da seleção natural, achava que ela fosse consideravelmente mais limitada do que na visão de Darwin, não podendo ser responsável, por exemplo, pela evolução da mente humana. Mais tarde se convenceu de que o mundo todo tinha sido criado para o homem; que a Terra ficava no centro da galáxia e era o único planeta habitável.

Mark Twain ironizou essa última posição num texto onde descreve brevemente o que ele supunha ser a história da evolução da vida na Terra, e compara a idéia de que essa longa história tem a espécie humana como objetivo final com a noção de que, se a torre Eiffel representasse a história da vida, a história humana seria a camada de tinta da bola de ferro decorativa no topo da torre, e estaria se sugerindo que toda a torre foi construída em função dessa fina camada de tinta no topo. "Duvido que qualquer um sugerisse isso. Eu não sei".

Texto introdutório de Steve Mirsky, do Science Talk, podcast da Scientific American.

(PS.: algumas hipóteses filogenéticas no texto, como de que os cangurus descendem das aves, estão erradas)



It was written in 1903. It's kind of a paleontological and anti-teleological rebuttal to Alfred Russell Wallace. Wallace was the co-founder of the theory of evolution by natural selection, but in his later years he became convinced that the entire universe had been created specifically as a venue for man. Twain—who often held humanity in relatively low esteem—felt compelled to respond to that assertion. So, here are some selections from the Mark Twain essay, "Was the World Made for Man?" from 1903.

It begins with a quote from the Literary Digest about Wallace's ideas:. “Alfred Russell Wallace's revival of the theory that this earth is at the center of the stellar universe and is the only habitable globe has aroused great interest in the world."

Twain now gives a long list of examples of how each organism in its time would have been utterly convinced that it was what everything had been created for, but they were all wrong—they were obviously all stepping stones on the way to man.

It was foreseen that man would have to have the oyster. Therefore the first preparation was made for the oyster. Very well, you cannot make an oyster out of whole cloth, you must make the oyster's ancestor first. This is not done in a day. You must make a vast variety of invertebrates, to start with—belemnites, trilobites, jebusites, amalekites, and that sort of fry—and put them to soak in a primary sea, and wait and see what will happen. Some will be a disappointment—the belemnites, the ammonites and such—they will be failures; they will die out and become extinct in the course of the 19 million years covered by the experiment. But all is not lost, for the amalekites will fetch the home-stake; they will develop gradually into encrinites, and stalactites, and blatherskites, and one thing and another as the mighty ages creep on and the Archaean and the Cambrian periods pile their lofty crags in the primordial seas, and at last the first grand stage in the preparation of the world for man stands completed, the oyster is done. An oyster has hardly any more reasoning power than a scientist has; and so it is reasonably certain that this one jumped to the conclusion that the 19 million years was a preparation for him; but that would be just like an oyster, which is the most conceited animal there is, except man. And anyway, this one could not know, at that early date, that he was only an incident in a scheme, and that there was some more to the scheme yet.

The oyster being achieved, the next thing to be arranged for in the preparation of the world for man, was fish—fish and coal to fry it with. So the old Silurian seas were opened up to breed the fish in, and at the same time the great work of building old red sandstone mountains eighty thousand feet high to cold-storage their fossils in was begun. The latter was quite indispensable, for there would be no end of failures again, no end of extinctions—millions of them—and it would be cheaper and less trouble to can them in the rocks than keep tally of them in a book. One does not build the coal beds and eighty thousand feet of perpendicular old red sandstone in a brief time—no, it took 20 million years. In the first place, a coal bed is a slow and troublesome and tiresome thing to construct. You have to grow prodigious forests of tree-ferns and reeds and calamites and such things in a marshy region; then you have, to sink them under out of sight and let them rot; then you have to turn the streams on them, so as to bury them under several feet of sediment, and the sediment must have time to harden and turn to rock; next you must grow another forest on top, then sink it and put on another layer of sediment and harden it; then more forest and more rock, layer upon layer, three miles deep—ah, indeed it is a sickening slow job to build a coal-measure and do it right!

So the millions of years drag on; and meantime the fish-culture is lazying along and frazzling out in a way to make a person tired. You have developed 10,000 kinds of fishes from the oyster; and come to look, you have raised nothing but fossils, nothing but extinctions. There is nothing left alive and progressive but a ganoid or two and perhaps half a dozen asteroids. Even the cat wouldn't eat such. Still, it is no great matter; there is plenty of time, yet, and they will develop into something tasty before man is ready for them. Even a ganoid can be depended on for that, when he is not going to be called on for 60 million years.

The Paleozoic time limit having now been reached, it was necessary to begin the next stage in the preparation of the world for man by opening up the Mesozoic age and instituting some reptiles. For man would need reptiles—not to eat, but to develop himself from. This being the most important detail of the scheme, a spacious liberality of time was set apart for it—30 million years. What wonders followed! From the remaining ganoids and asteroids and alkaloids were developed by slow and steady and pains-taking culture those stupendous saurians that used to prowl about the steamy world in those remote ages, with their snaky heads reared forty feet in the air and sixty feet of body and tail racing and thrashing after. All gone, now, alas—all extinct, except the little handful of Arkansawrians left stranded and lonely with us here upon this far-flung verge and fringe of time.

Yes, it took 30 million years and 20 million reptiles to get one that would stick long enough to develop into something else and let the scheme proceed to the next step.

Then the pterodactyl burst upon the world in all his impressive solemnity and grandeur, and all Nature recognized that the Cenozoic threshold was crossed and a new period open for business, a new stage begun in the preparation of the globe for man. It may be that the Pterodactyl thought the 30 million years had been intended as a preparation for himself—for there was nothing too foolish for a Pterodactyl to imagine—but he was in error: the preparation was for man. Without doubt the pterodactyl attracted great attention, for even the least observant could see that there was the making of a bird in him. And so it turned out. Also the makings of a mammal, in time. One thing we have to say to his credit—that in the matter of picturesqueness he was the triumph of his period; he wore wings and had teeth, and was a starchy and wonderful mixture altogether, a kind of long-distance premonitory symptom of Kipling's marine:

'E isn't one O'the reg'lar Line,

nor 'e isn't one of the crew,

'E's a kind of a giddy harumfrodite [hermaphrodite]–

soldier an' sailor too!

From this time onward for nearly another 30 million years the preparation moved briskly. From the Pterodactyl was developed the bird; from the bird the kangaroo; from the kangaroo the other marsupials; from these the mastodon, the megatherium, the giant sloth, the Irish elk, and all that crowd that you would make useful and instructive fossils out of—then came the first great ice sheet, and they all retreated before it and crossed over the bridge at Bering's strait and wandered around over Europe and Asia and died. All except a few, to carry on the preparation with. Six glacial periods with two million years between Periods chased these poor orphans up and down and about the Earth, from weather to weather—from tropic swelter at the poles to Arctic frost at the equator and back again and to and fro, they never knowing what kind of weather was going to turn up next. And if ever they settled down anywhere the whole continent suddenly sank under them without the least notice, and they had to trade places with the fishes and scramble off to where the seas had been, and scarcely a dry rag on them. And when there was nothing else doing a volcano would let go and fire them out from wherever they had located. They led this unsettled and irritating life for 25 million years, half the time afloat, half the time aground, and always wondering what it was all for, they never suspecting, of course, that it was a preparation for man and had to be done just so or it wouldn't be any proper and harmonious place for him when he arrived.

And at last came the monkey, and anybody could see that man wasn't far off now. And in truth that was so. The monkey went on developing for close upon five million years, and then turned into a man—to all appearances.

Such is the history of it. Man has been here 32,000 years. That it took a hundred million years to prepare the world for him is proof that that is what it was done for. I suppose it is. I don’t know. If the Eiffel Tower were now representing the world's age, the skin of paint on the pinnacle-knob at its summit would represent man's share of that age; and anybody would perceive that that skin was what the tower was built for. I reckon they would, I don't know.”

http://www.sciam.com/podcast/episode.cfm?id=013429DB-E7F2-99DF-341402C912A40D31