Is There Progress in Evolution
Discussion
Taken Richard Dawkins evolutionary views in The Selfish Gene and other books, and here, in a review of a book by Stephen Jay Gould, does evolutionary theory allow for progress ?
A summary by Frank Visser:
"Dawkins argues for a more "adaptationist" definition of progress (which he elaborates on more fully at the end of his magnificent The Ancestor's Tale):
- a tendency for lineages to improve cumulatively their adaptive fit to their particular way of life, by increasing the numbers of features which combine together in adaptive complexes. (p. 244)
If increased complexity increases that adaptive fit, it is selected, if not, not. The same for humanly cherished qualities such as consciousness. So this definition does not make one species paradigmatic for all others.
Dawkins continues:
- To evolution: Is it progressive? Gould's definition of progress is a human-chauvinistic one which makes it all too easy to deny progress in evolution. I shall show that if we use a less anthropocentric, more biologically sensible, more 'adaptationist' definition, evolution turns out to be clearly and importantly progressive in the short to medium term. In another sense it is probably progressive in the long term too (A Devil's Chaplain, p. 244)
- By this definition, adaptive evolution is not just incidentally progressive, it is deeply, dyed-in-the-wool, indispensably progressive. It is fundamentally necessary that it should be progressive if Darwinian natural selection is to perform the explanatory role in our world view that we require of it... (p. 248)
And about us humans, progress is acknowledged wholeheartedly, and not "grudgingly" as McIntosh would say, though putting it in the wider context of other forms of life:
- Progressive increase in brain size is to be expected only in animals where braininess is an advantage. This may, for all I know, constitute a minority of lineages. But what I do insist is that in a majority of evolutionary lineages there will be progressive evolution towards something. It won't, however, be the same thing in different lineages... And there is no general reason to expect a majority of lineages to progress in the directions pioneered by our human line (p. 251)
Even in the long run, Dawkins sees room for evolution's progress, using his concept of "evolvability":
- Evolution itself may evolve, progressively, over a longer timescale... [T]here really is a good possibility that major innovations in embryological technique open up new vistas of evolutionary possibility and that these constitute genuinely progressive improvements. The origin of the chromosome, of the bounded cell, of multicellularity, of gastrulation, of molluscan torsion, of segmentation—each of these may have constituted a watershed event in the history of life. (p. 254-255) "