Autor: Mehrere Autoren: Theological Studies; 01-SEP-06

Buch: Theological Studies; 01-SEP-06

Titel: Byrne, Patrick H., Evolution, randomness, and divine purpose: a reply to Cardinal Schonborn

Stichwort: Evolution; Design: Argument (William Paley, Michael Behe) - Gegenargument (Kenneth Miller)

Kurzinhalt: One common argument runs like this: A particular natural phenomenon has a pattern that could not have been produced by any sequence of natural causes: therefore, a transcendent designer ...

Textausschnitt: 2e The kind of argument used by proponents of intelligent design seeks to find signs not merely of design, but of design by intervention. One common argument runs like this: A particular natural phenomenon has a pattern that could not have been produced by any sequence of natural causes: therefore, a transcendent designer must have intervened in the ordinary course of events at some place and time to produce this pattern: therefore God exists. Although this type of argument has a long history, the most influential of such arguments were presented by English divine William Paley in 1802. He began with a famous analogy: If a watch were found lying in a field, one would appropriately infer that it was designed by a designer.1 Each of its parts was designed for a purpose in the overall functioning of the watch, which itself has the purpose of aiding human beings in telling time. Likewise, the intricacies of biological organisms occurring in nature also point to a designer. Beginning with the structure of the eye, Paley explored the interconnections among parts of many organisms, arguing that these complexities and their fitness for their functions are evidences of a divine designer. (Fs)

2f Paley's arguments are no longer widely accepted, but more sophisticated versions have since appeared. A recent and sophisticated version has been set forth by Michael Behe2, professor of biochemistry at Lehigh University. He describes in careful detail several complex biochemical pathways and structures that play crucial roles in organic functioning. One of his most impressive discussions concerns blood clotting: a more than 20 distinct and intricately related biochemical sequences are needed to initiate (and bring to a halt) this protective response to a wound. Behe argues that these sequences are "irreducibly complex," such that the removal of even one of the chemical reactions terminates the entire sequence. For this reason, he argues, these irreducibly complex sequences must emerge entirely whole--all or nothing. This means, he continues, that the irreducibly complex sequences could not have evolved piece by piece through normal evolutionary processes of variation. Therefore they must have been produced by an intelligent designer. Behe deliberately refrains from calling this designer God, but, if his argument were valid, such a conclusion would immediately follow. (Fs)

2g However, as Kenneth Miller, professor of biology at Brown University, has argued, Behe's irreducibly complex cycles could have resulted through a series of modifications to less complex sequences.3 Originally the less complex sequences could have had different biological functions that shifted to novel functions as a result of the successive modifications. Although neither Miller nor anyone else has stood watch for the thousands or millions of years that would be required to actually observe the entire series of such transformations, his proposals undermine the logic of Behe's design argument. Behe's argument depends on the claim that the cycle could not possibly have been produced by any random sequence of natural causes, so the intervention of a designer is needed to explain its existence. Miller and others have shown that at least there are such possibilities--and indeed possibilities supported by considerable empirical evidence--so the logic of Behe's argument fails. (Fs)

2h A different type of argument from design, however, one quite distinct from the type advanced by Paley, Behe, and others and not vulnerable to the same criticisms, can be advanced. But before considering this second type of argument, it is necessary to clarify the concept of randomness that is crucial to Schonborn's argument. (Fs)