Eliaqim a écrit :
- Une logique que je vien de trouvé sur le net;
1 Prenez un roman dans votre bibliothèque ;
2 Recopiez une des pages du roman à l’écran de votre ordinateur ;
3 Faites varier le contenu de la page aléatoirement ; vous supprimez, ajoutez, permutez des caractères pendant des heures aléatoirement ;
4 Est-il concevable, même sur des millénaires, qu’à un moment où à un autre, votre page résultante constitue une suite de phrases dans la langue initiale du roman ? Il faudrait que les dizaines de phrases de votre page soient toutes construites selon les règles de grammaire et sans erreur d’orthographe ;
5 Est-il concevable que votre page, même si elle répondait au critère du point 4, constitue une suite logique de l’histoire du roman à l’endroit où elle est insérée ?
6 Si la résultante, à un moment où à une autre, répond aux critères des points 4 et 5, vous la sélectionnez et vous la publiez. C’est la «sélection naturelle» dont les évolutionnistes font la promotion !
Salutation
Ah que je suis tanné de lire cet exemple ridicule des créationnistes. C'est faux, les évolutionnistes ne prétendent absolument pas que la sélection naturelle est un processus purement aléatoire!
Ce sont les créationnistes qui tentent de faire croire à tous le monde que c'est l'argument des évolutionnistes mais c'est faux!
La sélection naturelle est une question de "contingence" (hasard + histoire). Si tu prends le même exemple avec le livre et que tu appliques le processus réel de la sélection naturelle (donc pas un processus purement aléatoire) la conclusion est tout autre...
Grandissez que diable!
"1.2.3 Statistical impossibility of proteins?
What about the argument concerning the statistical improbability of obtaining a specific 141 amino acid sequence by looking for the correct sequence among randomly generated sequences? Certainly this mechanism could not explain the origin of protein sequences, but the creationist suggestion that this mechanism is part of evolutionary theory is false; it is a "straw-man" -- a false creationist caricature of evolution -- used repeatedly by creationists to mislead naive audiences into thinking that evolution is illogical. It is false because it demands a specific sequence in a SINGLE selection step from a pool of random sequences, whereas the real evolutionary model for the origin of protein sequences involves MULTIPLE ROUNDS OF RANDOM MUTATION followed by MULTIPLE selection steps as outlined above.
In a beautiful discussion of the distinction between these two models, British biologist Richard Dawkins (The Blind Watchmaker New York, 1986) simulated the creationists' straw-man caricature on a computer. He programmed the computer to generate random sequences to see if it would ever generate a line from Hamlet: "Methinks it is a weasel." This line has 28 characters (including spaces), so the computer was programmed to make 28 selections from the 27 possible characters (26 letters plus space). A typical output was
MWR SWTNUXMLCDLEUBXTQHNZVJQF
Since there are 2728 different possible ways of choosing from 27 alternatives 28 times, one can calculate the probability of picking the correct sequence and, based on the speed of the computer, estimate how long on average one would have to wait for the correct sequence to be printed. Dawkins figured a million million million million million years. If this were the best way protein evolution could be conceptualized -- by selection in a SINGLE step from random sequences -- one might conclude, along with the creationists, that a protein sequence could not have evolved. But the creationists' single step selection model is clearly a "straw-man" designed to ridicule the concept of randomness as a component of evolution. The real evolutionist model is that modern amino acid sequences evolved by successive steps in which random mutations of pre-existing sequences were subjected to selection; any rare mutant that provided more efficient function was propagated to future generations, in which the process of mutation and selection was repeated over and over. When Dawkins terminated his computer program simulating the straw-man "creationist version" of evolution and rewrote a program that more closely approximates the "evolutionist version" of evolution, the results of the simulation were quite different. Dawkins programmed the computer to generate an initial sequence randomly, as in the first model, and the computer produced:
WSLMNLT DTJBKWIRZRESLMQCO P
Then, following Dawkins's revised program, the computer made multiple copies (progeny) of this sequence, while introducing random "errors" (mutations) into the copies. The computer examined all the mutated progeny and selected the one that had most similarity (however slight) to the line from Hamlet. This selected sequence was used as the basis for another generation of progeny with further mutations, from which the best copy was again selected -- and so on. By ten generations, the sequence had "evolved" to
MDLDMNLS ITJISWHRQREZ MECS P
By thirty generations, it was:
METHINGS IT ISWLIKE B WECSEL
Instead of taking millions of years, the computer generated METHINKS IT IS LIKE A WEASEL in about half an hour, at the forty-third generation. Thus a cumulative multi-step model is not at all implausible as a model for evolution, given both a mechanism for replicating imperfect copies and a strong selective pressure. (The replication mechanism is, of course, a big "given"; how such a mechanism might have developed is a separate question concerning the origin of life rather than its evolution, and is not the subject of this article.) The importance of Dawkins's simulation is that it highlights the error of all the creationist arguments against the statistical improbability of evolution, by showing that the creationists' choice of a single-step versus cumulative multi-step model creates a falsely low estimate of the potential for deriving a particular sequence via random mutation and selection. Although both the single-step model and the cumulative multi-step model involve random sequences and selection, the predicted consequences of the two models are very different. The creationists ignore this difference and intentionally discuss only the model that gives the result they like, even though this model corresponds least well to the theory of evolution."
Sherkan