We have already seen thinkers like Ray Kurzweil and Hans Moravec defend the idea that cosmic evolution is progressive. But what of biological progress? The debate between those who defend evolutionary progress and those who deny it has been ongoing throughout the history of biology. On the one hand, more recent biological forms seem more advanced, on the other hand no one agrees on precisely what progress is.
Darwin’s view of the matter is summarized nicely by Timothy Shanahan: “while he rejected any notion of evolutionary progress, as determined by a necessary law of progression, he nonetheless accepted evolutionary progress as a contingent consequence of natural selection operating within specified environments.”[i] This fits well with Darwin’s own words:
There has been much discussion whether recent forms are more highly developed than ancient . . . But in one particular sense the more recent forms must, on my theory, be higher than the more ancient; for each new species is formed by having had some advantage in the struggle for life over other and preceding forms I do not doubt that this process of improvement has affected in a marked and sensible manner the organization of the more recent and victorious forms of life, in comparison with the ancient and beaten forms; but I can see no way of testing this sort of progress.[ii]
The most vociferous critic of biological progress was Harvard’s Stephen Jay Gould (1941 – 2002) who thought progress an annoying and non-testable idea that had to be replaced if biological history were to be understood. What we call evolutionary progress is really just a random moving away from something, not an orienting toward anything. Starting from simple beginnings, organisms become more complex but not necessarily better. In Gould’s image, if a drunk man staggers from a wall that forces him to move toward a gutter, he will end up in the gutter. Evolution acts like that wall pushing individuals toward behaviors that are mostly random but statistically predictable. Nothing about it implies progress.
The biologist Richard Dawkins is more sanguine regarding progress, arguing that if we define progress as adaptive fit between organism and environment then evolution is clearly progressive. To see this consider the predator/prey arms race, where positive feedback loops drive evolutionary progress. Dawkins believes in life’s ability to evolve further, in the “evolution of evolvability.” He believes in progressive evolution.
Darwin seemingly reconciled these two views.
… as the forms became complicated, they opened fresh means of adding to their complexity … but yet there is no necessary tendency in the simple animals to become complicated although all perhaps will have done so from the new relations caused by the advancing complexity of others … if we begin with the simpler forms & suppose them to have changed, their very changes tend to give rise to others.[iii]
Simple forms become increasingly complex, thus stimulating the complexity of other forms. This did not happen by necessity and no law need be invoked to drive the process, nonetheless competition between organisms will likely result in progressively complex forms.
There is probably no greater authority on the idea of evolutionary progress than Michael Ruse whose book, Monad to Man: The Concept of Progress in Evolutionary Biology, is the most comprehensive work on the subject. Ruse observes that museums, charts, displays, and books all depict evolution as progressive, and he thinks that the concept of progress will continue to play a major role in evolutionary biology for the following reasons. First, as products of evolution, we are bound to measure it from our own perspective, thus naturally valuing the intelligence that asks philosophical questions. Second, whatever epistemological relativists might think, nearly all practicing scientists strongly believe their theories and models get closer to the truth as science proceeds. From there scientists typically transfer that belief in scientific progress to a belief in organic progress. Finally, Ruse maintains that the kinds of scientists drawn to evolution are those particularly receptive to progressive ideas. Evolution and the idea of progress are intertwined and nearly inseparable.
[i] Timothy Shanahan, “Evolutionary Progress from Darwin to Dawkins,” http://biophilosophy.ca/Teaching/6740papers/shanahan.pdf
[ii] Charles Darwin, On the Origin of Species by Means of Natural Selection, or, the Preservation of Favoured races in the Struggle for Life (New York: Cosimo, Inc., 2007), 211.
[iii] Barrett, P., Gautrey, P., Herbert, S., Kohn, D., and Smith, S., Charles Darwin’s Notebooks, 1836-1844 (Ithaca: Cornell University Press, 1987).