He sketched branching descent, then a genealogical branching of a single evolutionary tree, in which “It is absurd to talk of one animal being higher than another”, discarding Lamarck’s independent lineages progressing to higher forms.
In the book Taking the Naturalistic Turn” the philosopher of science, Eliot Sober makes this point, clearly: “One of Darwin’s main contributions to our understanding of evolution was the elaboration of a new mode or pattern of explanation… . It contrasts with another, older pattern of explanation, which he has called “developmental explanations.”
The Lamarckian notion of “lineages progressing to higher forms” was steeped in developmental logics which covers the period of the individual from prenatal development to birth to death. Development describes the pattern that conserves the individual through continuous change in time, and leads to conclusions like family lineages progressing to new, higher forms and eventually on to new species. Developmentally speaking, the new forms are founded upon the most recent (highest developed) forms or in this case, family lineages. But, as Darwin discovered, looking over the fossil record, or observing variation of forms across species, a new kind of explanation was needed. Darwin was looking for a way to describe a pattern varies only at the population/species level, through syncopated change across individual lifetimes, resulting in the branching structure he drew as his evolutionary “tree,” where new forms descend from common ancestors deeper in the evolutionary past.
Today we know that evolution requires a much larger theater of explanation. Evolution is not only the story and pattern of species, but the story and shape of entire ecologies– the theater where species and environment engage in a co-adaptive dance. Evolution is bi-directional and loopy– natural selection in the environment causes adaptive variation in the species, which in turn causes variation in the environment. And still we are searching for an adequate theory of human evolutionary ecology.
Now, going back to our story about people and climate change, we can see the dangers of having a developmental bias beneath our notions of what it is to be human on an evolving planet. We can see that we subconsciously play a kind of bait and switch game with our ideas. We understand that the planet and everything else on it is evolving, but we pretend that humans will just go on and on developing into higher and higher stages rather than evolving through co-adaptation. We put one foot in nature and accept our evolutionary inheritance that brought us here, but take the other foot out when it comes time to talk about our evolutionary bequeathment.
Like all other species, humans are engaged in an co-adaptive dance with the environment. Yet for humans this “environment” is now global in scale. Like all other species, humans are biologically wired to optimize the development of their species, and live, die or adapt to the consequences. But ever since Darwin, unlike any other species,humans are able to contextualize their own development with respect to their co-adaptive partners– with respect to the other species, with respect to and for the earth.
Like all other species, we receive our present form from the sum-total of the entire evolutionary past. And like all other species, we set the possibility of our future from the sum total of the entire evolutionary possibilities — which means all of us for as long as possible, and depends upon as many different kinds of as possible — until “we” — that is all of us together– become the change that evolution inevitably seeks, as some of us sink into the fossil record as a species, perhaps, or perhaps not, noted for its unique ability to break through the species-centered, developmental bias, to have consciously co-evolved into a new existence. continue on to the next installment…