More philosophy of biology...hold on!

I was reading some more of Michael Ruse's Mystery of Mysteries last night. Not only does it have a fascinating point of its own to make (that the theory of evolution is in part, but not wholly, a social construction), but on the way, it really illuminates what a lot of other thinkers have been throwing out there. Take the late Stephen Jay Gould for instance. You may recall that he was famous--and appeared on "The Simpsons"--in part because he was able to "popularize" the concept of "punctuated equilibrium" (PE). PE basically means that micro-evolution/natural selection (i.e., genotypic mutations being selected for by the environment) cannot possibly account for the huge leaps in morphology (i.e., body plans of plants and animals) over time (what we call macro-evolution). Gould postulated that there must be times when evolution jumps forward, punctuating the general equilibrium, to begin a new type of species. Gould thought that this punctuation was a function of blind chance. The overall effect of the theory was to clash pretty dramatically with staunch macro-evolutionists and eventually to slide the theory of PE into most college-level biology textbooks as a "real, accepted theory of evolution." Richard Dawkins of The Selfish Gene fame has never been comfortable with PE because instead of pointing at gradual development of all life toward some imaginary goal of becoming more fit (without a divine Watchmaker, of course), it seems everything is very, very accidental and still strangely planned. But enough about my ideas, let's hear from Ruse (covering Gould).... "And what all this means is this: although in some particular instance the pressure for change may build up, no immediate--certainly no general smooth--change is possible. The constraints rule it out. Then, as it were, in some cases the dam may break, the constraints may give way, and a rapid change may occur, switching organisms to radically new forms. However, since these changes are rare, one would not generally expect to find them at the microlevel. One would spot them only by turning to long-term studies, that is, to evolution at the macro-level. "Most importantly, one could not expect to explain such constraint-breaking changes purely in lower-level terms--natural selection and so forth. They are exceptional. Yet, although exceptional and inexplicable in lower-level terms, the changes one sees in the broader, macro perspective do have implications for our understanding at the lower level. Not only is reductionism challenged in the sense of the belief that everything at the upper level [macroevolution] can be explained in terms of the lower level [microevolution through natural selection], but it is also challenged in the sense of the belief that the upper level can never have relevance for understanding causal mechanisms at the lower level. "Precisely because time does show that evolution can involve massive rapid (instantaneous or near-instantaneous) change, we should be very wary of claims about ubiquitous adaptationism. Perhaps the constraints of development mean that the new forms of organisms, their Baupl‰ne [something like "body plans" or morphological/structural tendencies], are not overwhelmingly functional. They are more accidental than anything else. Which menas that adaptation is very much less widespread than is dreamt of in the Darwinian heaven. To assume otherwise--to assume that adaptation is general--is to indulge in..."Just So" stories (so named after Rudyard Kipling's fantastical accounts of adaptations like the elephant's nose)." --Michael Ruse, Mystery of Mysteries: Is Evolution a Social Construction? (1999). pp.140-141.


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