What should scientists do when they encounter evidence of the history of life that does not fit their expectations?
Physicist Gerald Schroeder recounts a remarkable example of a scientist who faced just this problem: Charles Doolittle Walcott, secretary (director) of the famed science centre, the Smithsonian Institution in Washington.
He stumbled on the Cambrian explosion fossils in the Burgess Shale in British Columbia, Canada.
As Schroeder tells it, paleontologist Walcott was combining a summer holiday with a field trip in the mountains of eastern British Columbia in 1909, on a ridge that connects Mount Wapta with Mount Field, at 5000 feet elevation.
Walcott noticed something unusual, and stopped to investigate. It was unusual. It was a fossil of a crustacean that was over five hundred million years old.
He did not have a problem figuring out how the fossil got there. At one time, the area was part of an ocean shelf in a warm climate.
His problem was accepting that this fossil would be there: As Schroeder tells it,
Some 550 million years ago, at the start of the Cambrian, the only life on Earth was the most simple of forms, one-celled bacteria, algae, protozoans, and some pancake-shaped life of uncertain definition known as Ediacaran fossils. There was no way evolution could have advanced life from one-celled protozoans to the complexity of this crustacean in the twenty or so million years of the Cambrian. There had simply not been the time for that development. Well into the 1970s, evolutionary theory assumed that in excess of 100 million years were needed for the basic body plans of advanced life to evolve from the simplicity of pre-Cambrian life. (p. 36)
Perhaps this was a fluke? No, it was no fluke. Walcott found more and more fossils. He shipped over sixty thousand back to the Smithsonian. He had found the equivalent of Noah's Ark. He found every animal phylum, or - as Schroeder puts it - the "basic anatomies" of all animal life forms today.
Cause for rejoicing? No, because there was a problem. The problem was that the find obviously did not support Darwin's theory of evolution:
"Eyes and gills, jointed limbs and intestines, sponges and worms and insects and fish, all had appeared simultaneously. There had not been a gradual evolution of simple phyla such as sponges into the more complex phyla of worms and then on to other life forms such as insects. According to these fossils, at the most fundamental level of animal life, the phylum or basic body plan, the dogma of classical Darwinian evolution, that the simple had evolved into the more complex, that invertebrates had evolved into vertebrates over one hundred to two hundred million year was fantasy, not fact. (pages 36-37)"
So the reigning theory was probably false. Walcott, remember, was the director of the Smithsonian Institution. And he had just discovered something very inconvenient for the Institution. So what did he do?
Well, he mentioned his spectacular find in Smithsonian Miscellaneous Collections, a publication read by few people. And then he put them in drawers and left them there. They did not receive the attention they deserved for eighty years.
Many people have tried to understand and explain why Walcott ignored the significance of his Cambrian fossils, but the most likely reason is that the fossils were not what he had expected to see. He ignored them in order to preserve a belief system.
Tuesday, February 19, 2008
Hiding Disconfirmatory Evidence
A long history of forthrightness and honesty: