The fundamental thrust of Gould’s argument is undoubtedly correct. What is more problematical is his idea that evolution does not travel an inherently progressive path:

Increasing diversity and multiple transitions seem to reflect a determined and inexorable progression toward higher things. But the palaeontological record supports no such interpretation. There has been no steady progress in the higher development of organic design. For the first two thirds to five-sixths of life’s history, monerans alone inhabited the earth, and we detect no steady progress from ‘lower’ to ‘higher’ prokaryotes. Likewise, there has been no addition of basic designs since the Cambrian explosion filled our biosphere (although we can argue for limited improvement within a few designs – vertebrates and vascular plants, for example).[71]

Gould argues, particularly in his book Wonderful Life, that the number of animal phyla (basic body plans) was greater soon after the “Cambrian explosion” than today. He says diversity has not increased and there are no long-term trends in evolution, and the evolution of intelligent life is accidental.

Here it seems to us that Eric Lerner’s criticisms of Gould are correct:

“Not only is there a huge difference between the contingencies that lead to the evolution of a particular species and a long-term trend in evolution, such as towards greater adaptability or intelligence, but Gould rests his case on facts that are an example of just such a trend!” says Lerner. “Over time, evolution has tended to concentrate more and more on specific modes of development. Nearly all chemical elements were in existence ten billion years ago or more. The types of compounds vital to life – DNA, RNA, proteins, and so on – were all present on earth some four billion years ago. The main kingdoms of life – animals, plants, fungi, and bacteria – have existed for two billion years; there have been no new ones in that time. As Gould shows, the main phyla have existed for six hundred million years, and the major orders (a lower grouping) for about four hundred million years.

“As evolution has sped up, it has become more and more specific, and the earth has been transformed by the social evolution of a single species, our own. This is exactly the sort of long-term trend that Gould, despite his great contribution to evolutionary theory, is ideologically determined to ignore. Yet it exists, as does the trend towards intelligence.”[72]

The fact that evolution has resulted in greater complexity, from lower organisms to higher ones, leading to human beings with large brains capable of the most complex tasks, is proof of its progressive character. That does not mean that evolution takes place in a straight ascending line, as Gould correctly argues; there are breaks, retrogressions, and pauses within the general progress of evolution. Although natural selection takes place in response to environmental changes (even of a local character), it nevertheless has led to greater complexity of life forms. Certain species have adapted to their environment and have existed in that form for millions of years. Other species have become extinct having lost out in competition with other more advanced models. That is the evidence of the evolution of life over the past 3.5 billion years.

The reason for Gould’s emphatic rejection of the notion of progress in evolution has more to do with social and political reasons than strictly scientific ones. He knows that the idea of evolutionary progress and “higher species” have been systematically misused in the past in order to justify racism and imperialism – the alleged superiority of the white man was supposed to give the nations of Europe the right to seize the land and wealth of the “lesser breeds without the law” in Africa and Asia. As late as the 1940s respectable men of science were still publishing “evolutionary trees” showing the white man on top, with the black and other “races” on separate and lower branches, a little higher than the gorillas and chimpanzees. When questioned about his rejection of the notion of progress in evolution as “noxious”, Gould justified himself as follows:

‘Progress is not intrinsically and logically noxious,’ he replied. ‘It’s noxious in the context of Western cultural traditions.’ With roots going back to the seventeenth century, progress as a central social ethic reached its height in the nineteenth century, with the industrial revolution and Victorian expansionism, Steve explained. Fears of self-destruction in recent decades, either militarily inflicted or through pollution, have dulled the eternal optimism of the Victorian and Edwardian eras. Nevertheless, the assumed inexorable march of scientific discovery and economic growth continue to fuel the idea that progress is a good and natural part of history. ‘Progress has been a prevailing doctrine in the interpretation of historical sequence,’ Steve continued, ‘and since evolution is the grandest history of all, the notion of progress immediately got transferred to it. You are aware of some of the consequences of that’.[73]

One can sympathise with Gould’s reaction to such ignorant and reactionary rubbish. It is also true that terms like “progress” may not be ideal from a strictly scientific point of view when applied to evolution. There is always the risk that it could imply a teleological approach, that is, the conception of nature as operating according to a pre-established plan, worked out by a Creator. However, as usual, the reaction has swung too far the other way. If the word progress is inadequate, it could be substituted by, say, complexity. Can it be denied that there has been real development in living organisms since the first single-celled animals until now?

There is no need to return to the old one-sided view of Man, the culminating point of evolution, in order to accept that the past 3.5 billion years of evolution has not just meant change, but actual development, passing from simpler forms to more complex living systems. The fossil record bears witness to this. For example, the dramatic increase in average brain size with the evolution of mammals from reptiles, some 230 million years ago. Similarly, there was a qualitative leap in brain size with the emergence of humans, and this, in turn, did not take place as a smooth quantitative process, but as a series of leaps, with Homo habilis, Homo erectus, Homo neanderthalis, and finally Homo sapiens, representing decisive turning points.

There is no reason to suppose that evolution has reached its limit, or that human beings will experience no further development. The process of evolution will continue, although it will not necessarily take the same form as in the past. Profound changes in the social environment, including genetic engineering, can modify the process of natural selection, giving human beings for the first time the possibility of determining their own evolution, at least to some degree. This will open up an entirely new chapter in human development, especially in a society guided by the free and conscious decisions of men and women, and not the blind play of market forces and the animal struggle for survival.

  1. Gould, S. Ever Since Darwin, p. 118.

  2. Lerner, E. op. cit., p. 402.

  3. Lewin, R. op. cit., p. 140.