Thursday, July 22, 2010

God, Man, Evolution, and the Burgess Shale

Christopher Hitchens has written a book entitled God Is Not Great. I do not intend to comment here on the book in general or on his thesis as indicated by the title. The purpose of this note is to discuss an interesting reference he made concerning evolution and man’s place in the order of things.

No one has ever accused Hitchens of being dull. Consider this opening to his chapter savaging those who would believe that man has a special place in the cosmos.
"The three great monotheisms teach people to think abjectly of themselves, as miserable and guilty sinners prostrate before an angry and jealous god who, according to discrepant accounts, fashioned them either out of dust and clay or a clot of blood. The positions for prayer are usually emulations of the supplicant serf before an ill-tempered monarch. The message is one of continual submission, gratitude, and fear. Life itself is a poor thing: an interval in which to prepare for the hereafter or the coming—or the second coming—of the Messiah.....On the other hand, and as if by way of compensation, religion teaches people to be extremely self-centered and conceited. It assures them that god cares for them individually, and it claims that the cosmos was created with them specifically in mind."It is the latter notion, that humans are the culmination of either God’s creation, or, if you prefer, the inexorable evolution towards consciousness and domination of the world around us, that arouses Hitchen’s ire. In response to this rather universal belief that humans have some intrinsic "specialness," he reminds us of some facts about the evolution of life on earth. He refers to the fossil discoveries recorded in the Burgess Shale and references a book by Stephen J. Gould, Wonderful Life: The Burgess shale and the Nature of History. If one wants a more casual reference, Gould wrote a Scientific American article entitled The Evolution of Life on Earth. My comments are taken from that article.

To understand the importance of the Burgess Shale one must first have an understanding of the history of evolution. Gould points out that the first evidence of cellular life emerged rather early in the planet’s history
"The oldest rocks sufficiently unaltered to retain cellular fossils—African and Australian sediments dated to 3.5 billion years....Thus, life on earth evolved quickly and is as old as it could be. This fact alone seems to indicate an inevitability, or at least a predictability, for life’s origin from the original chemical constituents of atmosphere and ocean."Evidence of multi-celled structures does not appear until about 600 million years ago. Then suddenly(?) about 500 million years ago the earth experienced what is referred to as the Cambrian explosion, a brief period (in terms of millions of years) at the beginning of the Cambrian era when many forms of life developed, most of which died out. The fossil records contained in the Burgess Shale provide some understanding of what was taking place during this period. From Gould again
"....maximal diversity in anatomical forms (not in number of species) is reached rather early in life’s multicellular history. Later times feature extinction of most of these initial experiments and enormous success within surviving lines. This success is measured in the proliferation of species but not in the development of new anatomies. Today we have more species than ever before, although they are restricted to fewer basic anatomies."In other words there were millions of anatomical experiments carried out during the Cambrian explosion, but only a few survived. This brings us to the point that Hitchens wishes to make: man is not the center of the universe, but, rather, he is an evolutionary quirk of extremely low probability. Again from Gould
"Humans arose, rather, as a fortuitous and contingent outcome of thousands of linked events, any one of which could have occurred differently and sent history on an alternative pathway that would not have led to consciousness...only one member of our chordate phylum, the genus Pikaia, has been found among these earliest fossils. This small and simple swimming creature , showing its allegiance to us by possessing a notochord, or dorsal stiffening rod, is among the rarest fossils of the Burgess Shale, our best preserved Cambrian fauna....Moreover, we do not know why most of the early experiments died, while a few survived to become our modern recognized traits unite the victors and the radical alternative must be entertained that each early experiment received little more than the equivalent of a ticket in the largest lottery ever played out on our planet—and that each surviving lineage, including our own phylum of vertebrates, inhabits the earth today more by the luck of the draw than by any predictable struggle for existence."Gould goes on to discuss other aspects of evolution. He claims that there is no evidence to support the notion that there is a path in evolution towards greater complexity. That means that if we want to consider ourselves as the most complex beast ever to evolve, we must also view ourselves as the statistical freak of the highest order. To place us further into the proper perspective, Gould reminds us that after all the luck we possessed up to that point we still required a meteor strike to wipe out all the dinosaurs in order for our species to thrive.

Thank you, Christopher, for bringing up this fascinating topic. But have you made the point you wished to make? A creationist could read this and conclude that God does indeed work in mysterious ways. Also, our status as a low probability event does not really detract from the feeling that we are special. In fact, it may enhance that notion.

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