DNA, informação, e o significado das moscas
Pareceu-me, por alguns comentários recentes, que há alguma confusão entre a informação contida numa sequência, o DNA como molécula, e o significado de uma mensagem. Vamos lá ver se desta vez consigo explicar melhor.
A palavra “mosca” tem significado porque se refere às moscas, à ideia de mosca, ou a alguém estar com a mosca. Este significado precisa de um ser inteligente (e que perceba Português) para ser compreendido. Mas a mosca não tem significado. É uma mosca, e não se refere a mais nada. O DNA, como a mosca, não tem significado. É o que é.
A informação, no sentido técnico, é independente do significado que lhe damos. Se temos uma sequência de bits no computador A e queremos reproduzi-la no computador B, A tem que transmitir informação para B. A teoria da informação permite-nos optimizar esta transmissão: se a sequência for estruturada podemos comprimi-la em menos bits; se não tiver qualquer regularidade, temos que a enviar por completo, e não podemos poupar bits. Por isso dizemos que uma sequência irregular (aleatória, num sentido lato e pouco rigoroso) tem mais informação.
Ora esta transmissão não depende do significado que a sequência de bits tem para nós. Os computadores, e a teoria da informação, não querem saber se é uma carta de amor, uma lista de insultos, ou a declaração do IRS. Aliás, grande parte do tráfego de informação digital relaciona-se com protocolos de transmissão, verificação de integridade das mensagens, endereçamento, e muitas outras mensagens que nenhum ser humano vê. Pode-se transmitir ou guardar informação sem que essa informação signifique o que quer que seja.
As propriedades dos objectos também são independentes dos significados que nós inventamos. A palavra “água” não mata a sede, e a água tem as mesmas propriedades físicas e químicas qualquer que seja o seu significado para nós. O significado dos símbolos que descrevem o DNA não afecta os processos em que o DNA participa. Se queremos moscas mutantes, temos que alterar o DNA das moscas; não basta editar o ficheiro de texto onde guardámos a sequência.
Em suma, a quantidade de informação e as propriedades dos sistemas biológicos não dependem do significado dos símbolos que inventamos. O perigo da metáfora do DNA como linguagem é esconder esta independência. Como alterações aleatórias num texto escrito tendem a estragar o seu significado, esta metáfora leva à conclusão que mutações no DNA reduzem a quantidade de informação. Mas é treta.
Imaginem uma população de moscas, todas geneticamente idênticas (um clone, no sentido técnico). Para codificar a informação genética desta população precisamos apenas de codificar esta sequência. Mas se nascerem 10 moscas com mutações diferentes temos que codificar estas alterações além da sequência original partilhada por todas as outras moscas. Ou seja, há mais informação genética na população (que é e o que interessa para a evolução).
O argumento criacionista da informação é um bom exemplo da abordagem criacionista em geral. A conclusão é obviamente absurda, pois as mutações introduzem genes novos na população, aumentando a informação genética. Mas pelo artificio de confundir população com indivíduo, baralhar os conceitos de significado e informação, e apresentar uma metáfora inadequada como se fosse uma boa analogia, conseguem concluir que a maior diversidade genética corresponde menos informação.
Estou completamente rendido ao teu blog. Parabéns!
ResponderEliminarEspecialmente interessante a quantidade e qualidade da informação relacionada com essa já épica (e idiota) batalha do criacionismo vs teoria da evolução. O que me tem dado armas importantes no campo da argumentação.
talvez uma boa forma de traduzir numa metáfora a informação contida no DNA ao invés de pensar em "letras", "frases", "capitulos" seja imaginando essa informação como uma pintura. É obvio que numa frase ao alterar, apagar ou adicionar uma palavra e/ou letras se muda, ou se pode mudar, todo o sentido inicial e dar origem a algo desconexo, numa pintura tal já não acontece. Numa imagem que traduza alguma informação muito facilmente se podem apagar ou adicionar elementos e manter a mesma informação, ou altera-la ligeiramente de forma a continuar a fazer sentido, ou até mesmo de forma a explicitá-lo ainda melhor! Talvez assim a ideia de que uma alteração no DNA só pode ser negativa, utilizando como argumentos "lógicos" o exemplo da escrita... se perceba que não faz qualquer sentido.
ResponderEliminarTEN MAJOR FLAWS OF EVOLUTION - REVISED
ResponderEliminarby Randy Alcorn (with additional editing by Jim Darnall). I wrote the following article many years ago, but it needed to be thoroughly revised and updated. Thanks to Jim Darnall for adding some important new information.
The complexity of living systems could never evolve by chance—they had to be designed and created. A system that is irreducibly complex has precise components working together to perform the basic function of the system. (A mousetrap is a simple example.) If any part of that system were missing, the system would cease to function. Gradual additions could not account for the origin of such a system. It would have to come together fully formed and integrated. Many living systems exhibit this (vision, blood-clotting, etc.). When you look at a watch, you assume there was a watchmaker. A watch is too complex to "happen" by chance. Yet such living systems are almost infinitely more complex than a watch. They could not be random—they simply had to be designed and created.
The high information content of DNA could only have come from intelligence. Information science teaches that in all known cases, complex information requires an intelligent message sender. This is at the core of the Search for Extra-Terrestrial Intelligence (SETI). DNA is by far the most compact information storage/retrieval system known. A pinhead of DNA has a billion times more information capacity than a 4-gigabit hard drive. Ironically, evolutionists scan the heavens using massive radio telescopes hoping for relatively simple signal patterns that might have originated in outer space, all the while ignoring the incredibly complex evidence of superior intelligence built into every human's DNA. While we're waiting to hear signs of intelligence behind interstellar communication, we're ignoring those built into us.
No mutation that increases genetic information has ever been discovered. Mutations which increase genetic information would be the raw material necessary for evolution. To get from "amoeba" to "man" would require a massive net increase in information. There are many examples of supposed evolution given by proponents. Variation within a species (finch beak, for example), bacteria which acquire antibiotic resistance, people born with an extra chromosome, etc. However, none of the examples demonstrate the development of new information. Instead, they demonstrate either preprogrammed variation, multiple copies of existing information, or even loss of information (natural selection and adaptation involve loss of information). The total lack of any such evidence refutes evolutionary theory.
Evolution flies directly in the face of entropy, the second law of thermodynamics. This law of physics states that all systems, whether open or closed, have a tendency to disorder (or "the least energetic state"). There are some special cases where local order can increase, but this is at the expense of greater disorder elsewhere. Raw energy cannot generate the complex systems in living things, or the information required to build them. Undirected energy just speeds up destruction. Yet, evolution is a building-up process, suggesting that things tend to become more complex and advanced over time. This is directly opposed to the law of entropy.
There is a total lack of undisputed examples (fossilized or living) of the millions of transitional forms ("missing links") required for evolution to be true. Evolution does not require a single missing link, but innumerable ones. We should be surrounded by a zoo of transitional forms that cannot be categorized as one particular life form. But we don't see this—there are different kinds of dogs, but all are clearly dogs. The fossils show different sizes of horses, but all are clearly horses. None is on the verge of being some other life form. The fossil record shows complex fossilized life suddenly appearing, and there are major gaps between the fossilized "kinds." Darwin acknowledged that if his theory were true, it would require millions of transitional forms. He believed they would be found in fossil records. They haven't been.
Pictures of ape-to-human "missing links" are extremely subjective and based on evolutionists' already-formed assumptions. Often they are simply contrived. The series of pictures or models that show progressive development from a little monkey to modern man are an insult to scientific research. These are often based on fragmentary remains that can be "reconstructed" a hundred different ways. The fact is, many supposed "ape-men" are very clearly apes. Evolutionists now admit that other so-called "ape-men" would be able to have children by modern humans, which makes them the same species as humans. The main species said to bridge this gap, Homo habilis, is thought by many to be a mixture of ape and human fossils. In other words, the "missing link" (in reality there would have to be millions of them) is still missing. The body hair and the blank expressions of sub-humans in these models doesn't come from the bones, but the assumptions of the artist. Virtually nothing can be determined about hair and the look in someone's eyes based on a few old bones.
The dating methods that evolutionists rely upon to assign millions and billions of years to rocks are very inconsistent and based on unproven (and questionable) assumptions. Dating methods that use radioactive decay to determine age assume that radioactive decay rates have always been constant. Yet, research has shown that decay rates can change according to the chemical environment of the material being tested. In fact, decay rates have been increased in the laboratory by a factor of a billion. All such dating methods also assume a closed system—that no isotopes were gained or lost by the rock since it formed. It's common knowledge that hydrothermal waters, at temperatures of only a few hundred degrees Centigrade, can create an open system where chemicals move easily from one rock system to another. In fact, this process is one of the excuses used by evolutionists to reject dates that don't fit their expectations. What's not commonly known is that the majority of dates are not even consistent for the same rock. Furthermore, 20th century lava flows often register dates in the millions to billions of years. There are many different ways of dating the earth, and many of them point to an earth much too young for evolution to have had a chance. All age-dating methods rely on unprovable assumptions.
Uses continue to be found for supposedly "leftover" body structures. Evolutionists point to useless and vestigial (leftover) body structures as evidence of evolution. However, it's impossible to prove that an organ is useless, because there's always the possibility that a use may be discovered in the future. That's been the case for over 100 supposedly useless organs which are now known to be essential. Scientists continue to discover uses for such organs. It's worth noting that even if an organ were no longer needed (e.g., eyes of blind creatures in caves), it would prove devolution not evolution. The evolutionary hypothesis needs to find examples of developing organs—those that are increasing in complexity.
Evolution is said to have begun by spontaneous generation—a concept ridiculed by biology. When I was a sophomore in high school, and a brand new Christian, my biology class spent the first semester discussing how ignorant people used to believe that garbage gave rise to rats, and raw meat produced maggots. This now disproven concept was called "spontaneous generation." Louis Pasteur proved that life only comes from life—this is the law of biogenesis. The next semester we studied evolution, where we learned that the first living cell came from a freak combination of nonliving material (where that nonliving material came from we were not told). "Chemical Evolution" is just another way of saying "spontaneous generation"—life comes from nonlife. Evolution is therefore built on a fallacy science long ago proved to be impossible.
Evolutionists admit that the chances of evolutionary progress are extremely low. Yet, they believe that given enough time, the apparently impossible becomes possible. If I flip a coin, I have a 50/50 chance of getting heads. To get five "heads" in a row is unlikely but possible. If I flipped the coin long enough, I would eventually get five in a row. If I flipped it for years nonstop, I might get 50 or even 100 in a row. But this is only because getting heads is an inherent possibility. What are the chances of me flipping a coin, and then seeing it sprout arms and legs, and go sit in a corner and read a magazine? No chance. Given billions of years, the chances would never increase. Great periods of time make the possible likely but never make the impossible possible. No matter how long it's given, non-life will not become alive.
The scientific method can only test existing data—it cannot draw conclusions about origins. Micro-evolution, changes within a species on a small scale, is observable. But evidence for macro-evolution, changes transcending species, is conspicuous by its absence. To prove the possibility of anything, science must be able to reproduce exact original conditions. Even when it proves something is possible, it doesn't mean it therefore happened. Since no man was there to record or even witness the beginning, conclusions must be made only on the basis of interpreting presently available information. If I put on rose-colored glasses, I will always see red. I accept the Bible's teaching on creation, and see the evidence as being consistently supportive of that belief. When dealing with origins, everyone who believes anything does so by faith, whether faith in God, the Bible, himself, modern science, or the dependability of his own subjective interpretations of existing data. I would rather put my faith in God's revealed Word.
by Randy Alcorn, Eternal Perspective Ministries, 2229 E. Burnside #23, Gresham, OR