Friday, 25 May 2007

Design on Earth by Victor Stenger

Theist (T): Do you really believe that you are descended from a monkey?
antitheist (A): No. I believe the evidence indicates that monkeys, humans, elephants, worms, peas, and all other known forms of life on earth descended from a common ancestor.


T: You can't prove that. No one saw it happen.
A: We cannot see everything with our eyes. Scientific data is accumulated in many other ways than visual observation. The existence of many identical DNA sections in all living things is very strong evidence for common descent.

T: What about all the scientists who don't believe in evolution?
A: All believe in some kind of change in the development of life on earth. Disagreements on details exist, and the theory has developed enormously since Darwin, so don't expect every detail to be unchanged from Darwin's time. The overwhelming majority of biologists regard the basic mechanism of evolution by natural selection as confirmed to a very high probability.


T: But, still, evolution is just a theory, not a fact.
A: It is both theory and, to a high degree of confidence, a fact as well. In science, theory is not equated with speculation. Established theories are made of hypotheses and deductions drawn from those hypotheses that are strongly supported by empirical evidence. Evolution by natural selection is as much a fact as gravity. Indeed, it is observed in nature and the laboratory. In a beautiful recent example, African elephants are evolving without tusks as those with tusks are killed for their ivory.


T: But only microevolutrion is observed. Macroevolution is not.
A: Define macroevolution. I would call elephant evolution macro!


T: Macroevolution is evolution of one species to another.
A: The evolution of species has been observed. See www.talkorigins.org/faqs/faq-speciation.html.


T: But no transitional forms have ever been found in fossils.
A: Transitional forms have been observed. See www.talkorigins.org/faqs/faq-transitional.html. Actually, every species is, in a sense, a transitional form.

T: If I find a watch, I can tell by looking at it that it was designed by an intelligent being. When I look at a human organ, such as the eye, it also shows evidence for design.
A: True, the watch was intelligently designed. Human organs, on the other hand, are not like watches. They show definite signs that they evolved with a large element of chance. For example, the light receptors of the human eye point backwards! See The Blind Watchmaker by Richard Dawkins for details on the evolution of the eye, which apparently occurred several times independently. Furthermore, what competent engineer would place waste disposal systems in a recreation area?


T: Didn't the famous astronomer (and atheist) Fred Hoyle compute a very tiny probability for a bacterium to be assembled by chance? He said it is as if a tornado swept through a junkyard and assembled a 747.
A: Yes. His estimate was one part in ten raised to the 40,000 power. But bacteria did not evolve by chance processes alone but by chance and natual slection. Dawkin's books show how natural selection greatly improves the odds for functioning organisms to evolve.

T: Biochemist Michael Behe has shown that certain biochemical systems are irreducably complex and so could not have evolved. In these systems, if you take away one part they no longer function, so the parts could not have evolved separately. One example is the bacterial flagellum.
A: Evolutionists have shown the error in Behe's reasoning. He neglected to account for the well-known fact that the functions of biological parts can change as evolution proceeds. Thus a part can evolve having one function, and then develop a new one as it becomes part of another system. For critiques of Behe, see Finding Darwin's God by Kenneth Miller (a Christian). Also, look at the website www.talkorigins.org/faqs/behe.html. This has links to much more.

T: Darwinian evolution is only one scientific theory for the development of life on Earth. An alternative theory called intelligent design is equally good at explaining the data. Furthermore, this theory is superior to evolution because it shows mathematically that complex, specified information, such as contained in biological structures, cannot be generated by material processes alone.
A: The most prominent design theorist is theologian William Dembski. Dembski has a degree in mathematics but has published only one paper in a mathematical journal, not about intelligent design. Neither Dembski nor others promoting intelligent design have published their theory in a scientific journal. From what has appeared in the lay media, intelligent design is not a theory on the par with evolution. It offers no alternative to evolution other than "Some powerful intelligent being did it." Design theorists insist that the "intelligent being" need not be God. Still, Dembski's book Intelligent Design is mostly theology, suggesting that his motive is to promote his religious beliefs rather than develop a scientific theory. Of course, he protests otherwise. Read the book for yourself and decide. In any case, Dembski makes fundamental technical errors in information theory and physics.His definition of infomation is not conventional. His definition of complex specified information is ambiguous. His "law of conservation of information" is provably incorrect. In his latest effort, No Free Lunch, he again misappropriates scientific results. As with his colleague Behe, many critiques can be found of Dembski's work. The following site contain links to essays on both sides of the subject: www.freethought-web.org/ctrl/intelligent-design.html. More material can be found in the links below.

T: The fact that intelligent design theory is not published in the scientific literature does not mean it is not science. The editors of scientific journals could be biased against it. In fact, Dembski's theory classifies as science because it is testable. He has proposed a filter that successfully picks out objects that we know are designed. Applying that filter to biological organisms, he shows that they are designed.
A: I am willing to allow for the sake of argument that intelligent design, in some aspects, is science. However, as I have indicated, it is bad science, indeed, provably wrong science in some instances. As for Dembski's filter, a scientific theory is not regarded as successfully tested when it simply agrees with already known empirical facts. When the filter tells us that a watch is designed and a rock is not, it is telling is nothing we did not already know. When the filter tells us that a mouse is designed, we cannot say whether this is correct or not based on other observations. Thus, it is incorrect to say that Dembski's filter is tested. The only way this can happen is if the filter makes some prediction that is later empirically verified. For example, suppose the filter is applied to Moon rocks and identifies some stucture within one as designed. Geologists looking at the same structure say it was produced by natural processes. Then, sometime later after all all independent analyses have been published, we are visited by aliens who inform us that they had designed that particular Moon rock. Then Dembski's filter would pass the test.

T: Still, it is hard for me to imagine how the complexity of life could be all the result of purely material processes.
A: Perhaps that is just a failure of imagination. Let me ask you a question: Why do you object to evolution?


T: Actually, it is Darwinism I object to, which I take to mean the notion that all life evolved from its origin by purely material processes including a large element of chance. If that is the case, then humanity is an accident. This deeply conflicts with my religious faith which teaches that humans were put on Earth for a divine purpose.
A: You make several good points here. Many theists accept evolution as scientifically sound and compatible with their faith--the Catholic church, for example. But this does not mean they accept Darwinism as you have defined it--a definition, by the way, with which I agree. Evolution-theists still believe in some kind of God-guided evolution. For example, God had to step in a million years or so ago to make sure homo sapiens sapiens evolved they way he wanted. This is not Darwinism; it is a form of intelligent design. You are absolutely right that Darwinism conflicts with the belief that humanity is special. Some theologians have argued that humanity is just one of many different ways that God may fulfill his purposes. That cannot be ruled out, but it is hardly the traditional belief of the great monotheistic religions.
T: You are trying to invoke God as a "scientific explanation." This is not the way I view God. To me, God is continually sustaining the universe.


A: Yes, I understand the theology and am not saying that such a God is logically impossible. I am simply pointing out that whether God acts continually or lets things run along and just occasionally pokes in his finger, such actions are incompatible with Darwinism. Any God who plays an important role in the universe must prouce observable effects, and observations fall in the realm of science.

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