segunda-feira, setembro 25, 2006

A Evolução, o Acaso, e o Bitoque

Outro argumento muito usado pelos criacionistas é que as proteínas, células, e seres vivos não podem ter surgido por acaso. Estou perfeitamente de acordo, pois se fosse por acaso não precisávamos da teoria da evolução. Se lanço uma moeda e sai coroa, não perco tempo a tentar perceber porquê. Calhou, e está o caso arrumado.

O problema é que os criacionistas confundem processos naturais com acaso e assumem que aquilo que não acontece por acaso acontece por intervenção divina. O que é estranho. Se a moeda sair coroa cinquenta vezes consecutivas, parece-me que dizer que foi a vontade dos deuses é o mesmo dizer que foi por acaso. São apenas formas diferentes de indicar algo que nem controlamos nem compreendemos.

Não quer dizer que tenhamos que rejeitar a intervenção divina como explicação (tenciono elaborar isto em breve), mas temos de a especificar melhor, pois seja deus ou seja a física que tenha feito a moeda cair cinquenta vezes coroa, só compreendemos o que aconteceu se compreendermos como aconteceu. E apenas a teoria da evolução explica o como. O criacionismo fica-se pelo quem.

Para propagar este mal entendido, os criacionistas fazem contas complicadas com o numero de combinações de aminoácidos numa proteína, e coisas afins, para mostrar como processos naturais estão «longe de explicar a origem da vida e a transformação de moléculas em pessoas» (Jónatas Machado, O Público, 8/9/06).

As contas em si são uma treta merecedora duma entrada dedicada neste blog, mas não tenho tempo para tudo. Por isso vou-me restringir ao maior obstáculo que os criacionistas têm que enfrentar com este argumento.

O bitoque.

Frita-se um tubérculo, um pedaço de bovino, e um ovo de Gallus gallus domesticus. Reduz-se a uma pasta amorfa por masticação. No estômago e no intestino, enzimas e bactérias decompõem-na em moléculas orgânicas simples, inanimadas, e suficientemente pequenas para penetrar na membrana intestinal. E ao fim de umas horas estas moléculas são parte do tecido vivo humano. E isto fazemo-lo desde que começamos a vida como uma única célula (se bem que nem sempre com bitoques, senão enjoava).

Aqui os criacionistas têm duas opções. Uma é defender o milagre da digestão, em que o seu deus está presente em cada intestino para transformar moléculas em pessoas. Mas penso que esta tornaria demasiado óbvio que o criacionismo é uma hipótese inútil. A alternativa é admitir que um processo químico transforma moléculas em pessoas sem intervenção divina. E admitir que processos naturais podem transformar tubérculos e bovinos em humanos. E mesmo quando a probabilidade de tal acontecer por acaso é ridiculamente pequena.

É claro que já começamos com uma célula humana, mas os criacionistas não explicam como essa célula surgiu. Dizem-nos quem a fez, mas não como a fez. Limitam-se a negar a possibilidade de quatro biliões de anos de química e biologia originarem essa célula, sem propor uma explicação alternativa. Mas a transformação de uma célula num humano adulto por processos naturais em poucas décadas mostra como este argumento é fraco. E, como explicação, até o bitoque é melhor.

5 comentários:

  1. Já estou a ver o próximo cabeçalho do "Diário Creacionista"

    DEFENSORES DA EVOLUÇÃO AFIRMAM QUE A ESPÉCIE HUMANA EVOLUIU DO BITOQUE.

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  2. Com o devido respeito, não gosto e não concordo com o sistema americano nestas coisas de números, donde são 4 mil milhões de anos de evolução e não 4 biliões.
    A idade do próprio universo é estimada em cerca de 13 mil milhões de anos e não 13 biliões à americana.

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  3. Caro Manuel,

    Obrigado pelo comentário. Concordo, e prometo ter mais atenção para as próximas vezes.

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  4. Um artigo interessante de www.icr.org (Institute for Creation Research)

    Evolution: Real Science or Nonsense? (#144)
    by Martin Estrin, M.A.
    Abstract
    If evolution means that a species changes to improve itself, it seems more logical that humans would grow hair to keep warm, reduce their diet to the most nutritious foods...
    "Remember now thy Creator in the days of thy youth, while the evil days come not, nor the years draw nigh, when thou shalt say, I have no pleasure in them" (Ecclesiasties 12:1).

    Humans don't seem very satisfied. There is always something else they feel they need. Where are they trying to get to? On the other hand, most apes are quite content. If I were to apply some home-spun logic to the theory of evolution, then I would logically have to believe that apes evolved from man.

    If evolution means that a species changes to improve itself, it seems more logical that humans would grow hair to keep warm, reduce their diet to the most nutritious foods, eliminate high mortgages by adapting to the outdoors, and do away with money, complex governments, saying what you don't mean, war, stress, traffic congestion, and genocide (which occurs when you let other members of your species needlessly starve). Apes have accomplished all this.

    Apes, by evolving from man, have "created" a more workable and more sane life-style. If the ultimate aim in a more advanced society is for peace and equity, then those who evolved into the ape species have certainly surpassed their forbears of the human species.

    Pass me a banana. I want to be an ape.

    Real Science Is Not Arbitrary

    Life—according to evolutionists—began when different chemicals, under the right circumstances, came together and formed
    a more complex unit which eventually developed into an organism.

    It took millions of years for life to begin because the right kinds of chemicals, initially, didn't know they were right for each other until, under some arbitrary, chance circumstances, they finally met and made a match. Then, it required millions of more years for organisms to co-mingle and become transformed into complex creatures.

    The key factor in the theory of evolution is that the right elements came together under arbitrary circumstances. It would have to be that way, because if the elements were to be put together in a planned, or predestined, or systematic way, there would need to be a force directing them. The life forms that resulted would, then, have been "created."

    Charles Darwin advanced the theory of evolution by natural selection in1859. As it was gaining wide acceptance in the scientific community in the 1920s, noted scientist Sir William Cecil Dampier wrote:

    The fundamental concepts of physical science, it is now understood, are abstractions, framed by our mind, so as to bring order to an apparent chaos of phenomena.

    In other words, some scientists believed it was valid to use an abstract a theory to provide a simple answer to something that they could not otherwise observe and called it "evolution science." Yet, what is true science? Is it merely theory, or is it demonstrated fact? Is it arbitrary and unpredictable, or specific and systematic? In true science, a theory may be the basis for inquiry and study; but until it is "proven up," it is only speculation. It is not scientific to guess at conclusions.

    In addition, whatever has been determined to be scientific fact always turns out to be part of an elaborate pattern. When you take a closer look at fact-based science, it is very systematic.

    Science looks at the way something is. Research may have to discover how it is. But once a discovery is made—for instance, the speed of light—it becomes a scientific fact because it repeats itself in exactly the same way. Scientific facts are consistent and predictable—from the simplest to the most complex.

    Two plus two is four; and two times two is four. It is absolute, conclusive, and unalterable. The way you do a certain calculation, whether basic math or complex algebra, is the way it will always be done, and it will always produce the same result. Physics. Chemistry. Electricity. Radio waves. Plant life. Animal life. The physical and life sciences are all very precise and systematic sciences. Each follows a specific pattern. There are basic forms of each, as well as scientific combinations. For example, you can "mate" an orange and a tangerine because they are from the same family. But you cannot mix apples and oranges, even though they are both fruits. Nor is there any logic or proof that an apple evolved from an orange, or an orange from an apple. Likewise, monkeys and humans may have many similar physical features and social behaviors, but that seems to be a rather thin link to conclude that humans are the offspring of monkeys.

    Furthermore, for anything to be considered scientifically true, it has to be something that can be duplicated. If evolution were true, wouldn't scientists be able to recreate the sequence of change that transformed monkeys into humans?

    Instead, scientists in the 1950s discovered that each organic species—both plant and animal—has a specific, complex code for its species. It is called DNA which are complex segments of information in a cell that determine what kind of a plant or animal something is. The DNA signature is unique for every species, plus every creature has a DNA pattern which is unique for it. In other words, "Joe" has a DNA code for the human species, as well as a DNA pattern unique to him.

    More importantly, that DNA pattern has to be in a specific sequence for each species. In humans, there are three billion bits (called nucleotides) of information which fall into a very precise DNA sequence.

    And this DNA sequence cannot, and does not, rearrange itself to create something new. DNA does not have the independent capacity to add nucleotides at will. Once a given program is established, it remains fixed in its basic sequence.

    So in terms of pure science, "evolution science" appears to be a contradiction—an oxymoron. Evolution is unpredictable and arbitrary, while science is systematic—based on a preexisting system. And in a broader sense, it does not seem the universe could have created itself arbitrarily and still be completely, totally, and in every regard, systematic.

    More Questions Than Answers

    Evolution faces additional problems besides not fitting into the standard definition of science. Despite the extensive research in this field, it has to be acknowledged that some 130 years after the theory was proposed, there are still more questions than answers.

    The Darwin concept of evolution was chiefly based on a cause-and-effect scenario: creatures changed and developed because of the necessity to adapt to new surroundings.

    In this century, various paleontologists have discovered bone fragments of skeletons which they claim are extinct creatures that are the "missing links" between apes and man, thus supposedly proving evolution, and proving that today's humans are better adapted than these other creatures of a bygone era.

    But what supporting evidence do we really have? Why are we so quick to believe that a one-of-a-kind, hunch-backed skeleton 400,000 years old is suddenly the "missing link"? A few years after this discovery, some different fossils—supposedly one million years old—were found in another part of the world and were called the "missing link." Is there a link between these two links? And where are all of the other missing links? Where is the chain of evidence that shows how the unique parts of creatures evolved? How did the eye develop? How did we get a heart, stomach, other organs, teeth, hearing, smell, nerves, muscles, bones, and skin all in one nice, neat package?

    And a sperm meets an egg, we get another creature, almost as easily as using the Xerox. For that matter, how did the distinction of male and female genders occur?

    How does evolution explain an unattractive, slithering caterpillar going into a chrysalis and emerging as one of nature's most delicately beautiful creatures—a butterfly?

    But the most basic and difficult question of all is: How did inorganic material make the transition to organic, living cells? In fact, this was one of the first questions raised about evolution theory. But the proponents of evolution past and present avoid it. I. L. Cohen points out in his book, Darwin Was Wrong—A Study in Probabilities: "The idea that life sprang spontaneously from dead inorganic matter was quietly set aside, under-emphasized, and virtually forgotten."

    With so many pertinent questions, and such weak science in the limited answers offered, at best, evolution seems to end up being a jigsaw puzzle with a significant number of pieces missing. Looking closely at the issues surrounding evolution, it seems perplexing that so many scientists still cling to and advocate it, even to the point of endorsing it as factual truth in science textbooks.

    The conclusion of I. L. Cohen is that "the constant repetition of a speculation did, unfortunately, extend it an aura of unwarranted credibility, which, in turn, embedded itself into our collective minds as established fact."

    Conclusion

    Are evolutionists disingenuous? In the beginning, the proponents of evolution theory asked that society become broad-minded to allow the free expression of their minority point-of-view. But now that Darwinists represent the majority viewpoint, they have become narrow-minded, forcing the exclusion in the free marketplace of ideas of differing opinions.

    In the most democratic of places—public schools—evolution has been elevated to a scientific gospel, and other concepts are no longer presented because they are heretical. But other ideas need to be given a forum. Indoctrination in only one viewpoint, demeans true science. Let's be more fairminded.

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  5. Um artigo interessante sobre o mito da evolução química. (www.icr.org)


    The Myth Of Chemical Evolution (#313)
    by David Rosevear
    Download The Myth Of Chemical Evolution PDF

    Abstract
    The ancient Greeks believed in the spontaneous generation of life. More recently, Louis Pasteur showed that life did not arise from non-living material. Yet those who deny the Creator's existence must believe it happened once upon a time. Evolutionists estimate the earth to be 4.6 billion years old and the earliest fossils about 3.8 billion years old.


    The ancient Greeks believed in the spontaneous generation of life. More recently, Louis Pasteur showed that life did not arise from non-living material. Yet those who deny the Creator's existence must believe it happened once upon a time. Evolutionists estimate the earth to be 4.6 billion years old and the earliest fossils about 3.8 billion years old. An initially hot Earth might take, say, 0.3 billion years to become "user friendly," so the first life took only about half a billion years to arrive from abiotic (non-living) starting materials. If it is as easy as just having the right conditions, one might think that life should have evolved many times before the advent of photosynthesis produced an oxygen concentration which made conditions unfavorable. Yet all life rides upon the same biomolecules, metabolic pathways, and genetic information, so life had but one origin, either created or evolved.

    Modern theories of the origin of life date back to the Soviet scientist Oparin in 1924. His ideas of a Primeval Soup were promoted in the West by fellow communist J.D.S. Haldane of Cambridge. In 1953 Urey & Miller published results of some simple experiments in organic chemistry which seemed to lend credence to the soup theory. Interestingly, forty years later, Miller admitted that the question of the origin of life is much more difficult than he, or anyone else, had thought. Clutching at straws, others have suggested mid-ocean ridges (with their cocktail of hot chemicals) as the cradle of life, while others have postulated an extraterrestrial seeding of the Earth. This latter suggestion still does not offer a mechanism for abiogenesis.

    With the development of molecular biology since the time of Oparin and Haldane, the cell is no longer regarded as simple. The living plasma membrane allows in or out only specific compounds. It is not simply a semi-permeable membrane. Cells contain nucleic acids that carry information about the structure and functions of the organism. They also contain ribosomes where proteins are made using a complex mechanism of nucleic acids and more than a hundred different proteins, each with a specific task. The cell also contains mitochondria where energy (ATP) is produced. The complexity of all these parts of the cell is enormous. Lynn Margulis has suggested that the first proto-cell assimilated these organelles by a process of symbiosis. However, these components cannot now exist independently, nor could the cell exist without their contributions. Moreover, one such type of organelle, known as a lysosome, contains enzymes whose function is to digest foreign bodies. With all the amazingly complex, mutually-dependent components, it seems that the cell had to be complete from the beginning, rather than being assembled piecemeal over years of evolution.

    The major biochemicals in living cells are proteins and nucleic acids. No biologically significant proteins or nucleic acids have been made by any experiments such as those of Miller or those who have followed him.

    Proteins are strings of amino acids whose enzymatic activities arise from active groups within a specific three-dimensional shape. These are due to a precise sequence of the amino acids. There are twenty amino acids found in proteins, although many others exist that are not used in metabolic pathways. Chemically they are NH2CH(R)COOH, where R is H in the simplest case, glycine, but can also be a variety of organic groups such as CH3 in alanine. In all amino acids except glycine, the central carbon is surrounded by a tetrahedron of four different groups, H, R, amine and carboxylic acid. Because of this asymmetry, amino acids exist in two forms, designated right- and left-handed (or d and l, or R and S). In proteins (a string of amino acids—NHCH(R)CONHCH(R¢)CO—etc. formed by condensing out of a molecule of water, HOH, between each pair), all amino acids are left-handed. This left-handedness gives the chain a spiral twist, leading to a specific 3D shape that is essential to its function. In the living cell, proteins are made by means of RNA and many specialized proteins (enzymes). Since proteins are needed to make proteins, it is not easy to speculate how a first protein could occur by chance processes.

    In laboratory experiments aimed at simulating conditions on a lifeless Earth, a messy mixture of amino acids can be formed, consisting of mostly glycine and d/l-alanine. Not all amino acids found in proteins can be synthesized in this manner, while many not used by living systems do result from these experiments. A product consisting of exclusively left-handed amino acids never results, and from theoretical considerations cannot result. Only d/l racemic mixtures are formed. Peptization, the joining of the amino acids to form a protein by the elimination of water, is difficult to accomplish by non-biological means. Proteinoids are unstable in the presence of water. Since they cannot replicate themselves, natural selection cannot be a driving force in their improvement. The precise order of amino acids in proteins in cells is governed by information on the nucleic acids that code for them, so this could not be achieved by chance. Moreover, the tar-like by-products would tend to poison any enzymatic activity in proteins.

    Nucleic acids are found in living cells as DNA, ribosomal-RNA, messenger-RNA and transfer-RNA, each with specific properties. They consist of strings of nucleotides, which are composed of a nitrogenous base, a sugar and a phosphate linkage. DNA carries the genetic information for the organism while RNA is used in protein synthesis. There are four different bases on the double-stranded DNA. The strands are linked by weak hydrogen bonds between bases on each strand. The structure of the bases is such that each in one strand only links with one other type of base in the other strand. One single strand of DNA therefore acts as a template for the other strand during cell replication. Three consecutive bases act as a codon to transfer information to specify a particular amino acid, or to start or stop a sequence. This information on a string of DNA (gene) is responsible for the formation of a particular protein. Since there are four bases, there are sixty-four codons (43), which pass information rather like the letters and punctuation of a written message. This is a precise mechanism. Information transfer is checked at a rapid rate by proteins for random changes, known as mutations, which lose information. No mutation could lead to an increase of information, so neo-Darwinism cannot be a mechanism for macroevolution. It is a tenet of Information Theory that information only comes from an intelligent source, so genetic information must have been created. Information not only implies meaning, but purpose. This is the opposite of chance. As a carrier of information the DNA molecule is 4.5x1013 (45 trillion) times more efficient than the silicon megachip, which was made by teams of designers. Incidentally, a stereo-chemical basis for the relationship between any particular three nucleotides and the amino acid for which they code has not yet been elucidated.

    When nucleotides are joined in the laboratory, thermodynamic considerations allow one particular site for bonding phosphate to sugar to the next phosphate. However, such a pseudo-DNA strand is not biologically useful. The bonding site found in DNA, the 3¢ and 5¢ carbons of ribose, is in the best position because the proteins used to join it together act as templates to get the junction across the sugar right. The sugars, deoxyribose in DNA, and ribose in RNA, are also chiral like the amino acids, but in this case the sugars are all right-handed. Again, there is no conceivable mechanism for arranging this by chance.

    Urey and Miller had to assume, contrary to the opinions of geologists, that the early Earth had no oxygen in its atmosphere. This is because amino acids are destroyed by oxygen. But absence of oxygen implies absence of ozone, another form of oxygen. Ozone in our atmosphere protects us from high energy ultra-violet rays from the Sun. Nucleic acids are rapidly decomposed by UV light. A further difficulty for those who postulate abiogenic synthesis is that the molecules formed are destroyed by the very conditions (such as heat, UV light and electricity) that make them. Proteins and polynucleotides are thermodynamically unstable. They are also unstable with regard to hydrolysis and reactions with other simple reagents. Moreover, the longer the experiment is allowed to continue, the more decomposition products are made. Many processes are reversible, and in the equilibrium state simpler starting materials predominate over more complex products. Time does not help the forward reaction. The tarry messes from these experiments are in stark contrast to the neat metabolic pathways of living cells with their clean, high yields of precisely fashioned products. In their experiments to simulate abiogenic development, investigators begin each stage with pure compounds in high concentrations. This can hardly reflect natural conditions on a prebiotic Earth.

    In the living cell, the DNA codes for proteins and the DNA is itself constructed using proteins. It is a chicken and egg situation. It has been suggested that RNA possesses some of the enzymatic properties of proteins while having the information carrying ability of DNA. Could positing a first proto-cell that relied on RNA for both functions, solve the problem? No primeval soup experiment has ever produced anything resembling RNA. RNA does not replicate itself, a prime necessity for a living cell. RNA's enzymatic properties are not sufficiently versatile for even the simplest imaginable proto-cell. The problem of the origin of information on the information carrying RNA remains unsolved. A proto-cell based solely on proteins is equally impossible, since proteins lack the ability to reproduce themselves.

    Each component of a living cell is breathtakingly complex, yet in isolation it cannot survive nor replicate itself. All the parts of the cell are necessary to its functioning and replication. Nothing works until everything works. This has been called irreducible complexity. Even small parts of the components of cells can be unimaginably complex. An example of this is the enzyme adenosine triphosphate synthase, found in all living cells including animals, plants, fungi and bacteria. The elucidation of the structure of ATP synthase won a 1997 Nobel Prize. Every cell contains hundreds of these miniature motors embedded in the surfaces of the mitochondria. Each is 200,000 times smaller than a pinhead. The motor forges a bond between ADP and phosphate to form ATP. The ATP couples with other processes in the cell requiring energy to reform ADP and phosphate. So energy is directed to contract muscles, beat the heart and drive thought processes in the brain, while the products are recycled. At the centre of ATP synthase is a tiny wheel that turns at about 100 revolutions per second and turns out three ATP molecules per rotation. Just to keep us thinking and walking, humans must recycle their own body weight of ATP each day. Each enzyme is composed of thirty-one separate proteins that in turn are made of thousands of precisely arranged amino acids. Take away any one of the 31 proteins and the motor is useless. It could not have evolved. And consider this: the genetic information and RNA plus proteins needed to construct the ATP synthase are in total even more irreducibly complex than the ATP synthase itself. (A car-making factory is more complex than a car.)

    The concept of abiogenesis is vital to the atheistic evolutionist. It follows in their thinking that if life can arise spontaneously under the right conditions, then there will be perhaps millions of planets in the Universe where life already exists. In some of these places intelligent life may have evolved. These ideas have spawned a large body of literature, films and video games involving imaginary extraterrestrial life. Billions of dollars have been spent by government sponsored searches for messages from out there (e.g., project SETI). The irony is that evolutionists would recognize that a nonrandom signal from space that carried information with meaning and purpose must have come from an intelligent extraterrestrial. Yet they consider nucleic acids in the living cell, a nonrandom sequence of nucleotides carrying far more information with precise meaning and exquisite purpose, and say it must have arrived by chance!

    * Dr. Rosevear is Director of the Creation Science Movement in England.

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