The Concept of Progress in Evolution
Life is so obviously a process in time and not merely a static condition of being that this study has always to some degree involved historical concepts. Development and progression are so plainly evident in animate nature that these features deeply impressed biologists long before the grand fact of the evolution that produced them was understood.
The idea of biological progress is as old as the science of biology and it was already deeply imbedded in pre-evolutionary science. Although its actual historicity and its real relationship to the flow of time were scarcely glimpsed, this concept of a progression of life from lower to higher was fundamental both in primitive theology (such as the Semitic Creation myths) and in primitive science (such as that of Aristotle), and it was taken over, more or less as a matter of course, in later pre-evolutionary biology that still stemmed, in the main, from these two sources.
Evolution, revealing the development of life as an actually and materially historical process, gave meaning to these older observations and to the almost intuitive concept of progression if not, fully, of progress. The first truly general and scientific theory of evolution, that of Lamarek, had as its central feature the very ancient and previously nonevolutionary idea of a sequence of life forms from less to more perfect.
Examination of the actual record of life and of the evolutionary processes as these are now known raises such serious doubts regarding the oversimple and metaphysical concept of a pervasive perfection principle that we must reject it altogether. Yet there is, obviously, progression in the history of life, and if we are to find therein a meaning we are required to consider whether this involves anything that we can agree to call “progress,” and if so, its nature and extent.
It is a childish idea—but one deeply ingrained in our thinking, especially on political and social subjects—that change is progress. Progression merely in the sense of succession occurs in all things, but one must be hopelessly romantic or unrealistically optimistic to think that its trend is necessarily for the good.
We must define
progress not merely as movement but as movement in a direction from
(in some sense) worse to better, lower to higher, or imperfect to
more nearly perfect…
The criterion natural to human nature is to identify progress as
increasing approximation to man and to what man holds good. The
criterion is valid and necessary as regards human history, although
it carries the still larger obligation of making a defensible and
responsible choice among the many and often conflicting things that
men have held to be good. The criterion is also perfectly valid
in application to evolution in general, provided we know what we
are doing.
Approximation to human status is a reasonable human criterion of progress, just as approximation to avian status would be a valid avian criterion or to protozoan status a valid protozoan criterion. It is merely stupid for a man to apologize for being a man or to feel, as with a sense of original sin, that an anthropocentric viewpoint in science or in other fields of thought is automatically wrong. It is, however, even more stupid, and even more common among mankind, to assume that this is the only criterion of progress and that it has a general validity in evolution and not merely a validity relative to one only among a multitude of possible points of reference…
As a start in the inquiry, it is quickly evident that there is no criterion of progress by which progress can be considered a universal phenomenon of evolution…
Whatever criterion you choose to adopt, you are sure to find that by it the history of life provides examples not only of progress but also of retrogression or degeneration. Progress, then, is certainly not a basic property of life common to all its manifestations. This casts further doubt (at least) on the finalist thesis, still more on the concept of a perfecting principle, but it certainly does not justify a conclusion that progress is absent in evolution. In a materialistic world the very idea of progress implies the possibility of its opposite. To find that progress is universal would certainly be far more surprising than to find that it is only occasional.
In the record of life, there seems to be only one progressive change that involves life as a whole, a tendency for life to expand, to fill in all the available spaces in the livable environments… This is one possible sort of progress... In this sense extinction is not merely the end but also the very antithesis of progress—but ultimate extinction (the inevitable fate of all life) is no sign that progress was earlier absent in the rise and history of the group. As regards direction and intensity of expansion at any one time, man is right now the most rapidly progressing organism in the world. The actual bulk of material incorporated in Homo Sapiens seems now quite clearly—and from other points of view, most unfortunately—to be increasing more rapidly than in any other species…
Control over the environment is still more clearly progress if we agree to consider progress frankly as defined from the human position. At least it lends us to the position that only man is really progressive in the history of life. Actual control of environment, as opposed to the ability merely to move about in search of suitable environments, means of escape from unsuitable ones, or the ability to get along in varied and varying environments, is almost exclusively a human ability…
The fact that control of environment is so nearly exclusive to man does not mean that it is not progress, but only that it is a peculiarly human sort of progress, part of the larger wonder that man is a new sort of animal that has discovered new possibilities in ways of life—and this is progress whether referred specifically to the human viewpoint or not.
However, progress may be defined among such broader ways as have now been exemplified… Increasing structural complication at once comes to mind, especially as evolution has so often and so misleadingly been generalized as just a succession from simple to more complex forms of life. This was an aspect of progress, and an important one, far back in the days of fundamental progress in successive occupation of the major and more radically different ways of life. The first step in this, beyond the protozoans was the rise of many-celled animals, which was progress involving complication of structure. Complication was also markedly involved in the rise of the diverse multicellular phyla, but again we find that this was progress in multiple lines, not a single process of increasing complication nor even a central line with branching blind alleys that might or might not be progressive in this respect…
In summary, evolution is not invariably accompanied by progress, nor does it really seem to be characterized by progress as an essential feature. Progress has occurred within it but is not of its essence. Aside from the broad tendency for the expansion of life, which is also inconstant, there is no sense in which it can be said that evolution is progress.
Within the framework of the evolutionary history of life there have been not one but many different sorts of progress. Each sort appears not with one single line or even with one central but branching line throughout the course of evolution, but separately in many different lines. These phenomena seem fully consistent with, and indeed readily explained by, the materialistic theory of evolution… They are certainly inconsistent with the existence of a supernal perfecting principle or with the concept of a goal in evolution.