Categories or Degrees of Existence (Agnosticism)

by dhw, Thursday, July 08, 2010, 21:24 (5251 days ago) @ David Turell

David has referred us to a new fossil find that proves the existence of multicellular organisms 2.1 billion years ago. They are too big and too complex to be prokaryotes or eukaryotes, and predate the earliest known multicellular life forms by 1.5 billion years.-It's amazing how many recent discoveries represent a "major breakthrough" in our understanding of life, the universe, the descent of man, the nature of the genome ... and yet it seems to me that each one tends to deepen the mysteries rather than solve them. -David asks, in the light of the new discovery and its relation to the Cambrian Explosion, "Where is Darwin's gradualism?" This is a point of the theory that I have never quite understood. Darwin is unequivocal about its importance: "If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down." (Origin, p. 214) In some respects he is on safe ground, because no-one can ever prove that there were no transitional forms, just as no-one can ever prove that there is no God. The Eldredge-Gould concept of 'punctuated equilibrium', however, contradicts that of 'Natura non facit saltum' and it certainly seems to be more in keeping with the fossil record as we know it. What I don't understand is why gradualism should be so crucial to the theory as a whole. Mutations and new combinations would account for some innovations, and the impact of environmental changes for others. How and why else would new organs come into being? In both cases, there would be jumps, after which natural selection would certainly bring about gradual improvements, but how complex does an organ have to be before we call it complex? A single cell alone is staggeringly complex. Either innovations work or they don't, and if they do, they are already complex, even if they survive and later become even more complex. It therefore seems to me that evolution doesn't depend on gradualism at all. Perhaps someone can enlighten me.-
*** This will be my last post for ten days or so, as my two-year-old grandson insists on his parents, my wife and me taking him on holiday to Cornwall. I suspect he will be teaching us more about life than all the Gabonese fossils put together.