Sunday, 24 February 2008
Harvard biologist admits: We know nothing about brain evolution
Science journals have featured countless stories about the evolution of the human brain. Scientists are puzzled since humans have much bigger brains than any other species. Their suggested explanations have often been mutually exclusive. For instance, the old text book explanation relied on eating meat but a few years ago an article in New Scientist, a popular science magazine, suggested that eating starch was the secret of brain growth.
But both explanations fail to answer why other meat or starch eating species do not have big brains.
At the recent AAAS (American Association for the Advancement of Science) annual meeting in Boston, Richard Lewontin, a distinguished biology professor at Harvard University, acknowledged that stories about human brain evolution have not been based on facts. Reporting on the meeting for the journal Science, Michael Balter quoted Lewontin as saying, “We are missing the fossil record of human cognition, so we make up stories."
The title of Balter’s article seems to be an admission of sorts: “How Human Intelligence Evolved--Is It Science or ‘Paleofantasy’?”
According to professor Lewontin, it is fantasy. Lewontin suggests that there is much cause for pessimism in the study of human origins.
Science reporter James Randerson of Britain’s Guardian newspaper was even more brunt, saying, “We know nothing about brain evolution.” Randerson went on to summarise Lewontin’s reasons for pessimism. “The handful of hominid fossils stretching back 4m years or so” cannot tell us whether any of them were our ancestors. We “do not have the have the faintest idea what the cranial capacity [of a fossil hominid] means”. Moreover, we do not even know which hominids walked upright and which did not.
Lewontin is well-known for his outspokenness. In 1997 he wrote in The New York Review of Books that scientists often choose to make up “unsubstantiated just-so stories” because they “have a prior commitment, a commitment to materialism… Moreover, that materialism is an absolute, for we cannot allow a Divine Foot in the door.”
Obviously, the scientific community cannot ignore Lewinton’s recent conclusions. If the ruling paradigm (naturalism or the view that nature is all there is) leads us into a blind alley, might there be something wrong with it?
Balter M. 2008. How human intelligence evolved -- Is it science or 'paleofantasy'? Science 319:1028.
Lewinton, Richard. 1997. Billions and billions of demons. The New York Review of Books, p. 31, (9 January 1997).
Randerson, James. 2008. We know nothing about brain evolution. Guardian February http://blogs.guardian.co.uk/science/2008/02/the_distinguished_biologist_pr.html