Thursday, August 27, 2009

Why 'evolution'?

“Evolution” is the label or single-word concept we use in English as shorthand for what we would otherwise describe as the intellectual contribution of Charles Darwin.

But is this term really the best choice?

Etymologically, the term is derived from the Latin evolvere, meaning unrolling, or unfolding. Merriam-Webster’s defines evolution variously as “a process of change in a certain direction”, “the process of working out or developing”, etc.

I think it’s safe to assume that to most people, the term connotes change. I know that’s what I used to think of when I heard the word “evolution”: a living species changing over time to become something new.

And here’s this, from a prominent book on science education standards (Science for All Americans), regarding Darwin’s intellectual contribution:

“…Prior to Darwin’s time, the prevailing view was that species did not change, that since the beginning of time all known species had been exactly as they were in the present….

One line of thought was that organisms would change slightly during their lifetimes in response to environmental conditions, and that those changes could be passed on to their offspring…

Darwin offered a very different mechanism of evolution. He theorized that inherited variations among individuals within a species made some of them more likely than others to survive and have offspring, and that their offspring would inherit those advantages. Over successive generations, advantageous characteristics would crowd out others, under some circumstances, and thereby give rise to new species.”

(Italics mine.)

So again we see: the focus is on change, undoubtedly a result of our use of the term “evolution” to encapsulate Darwin’s main idea.

I propose to challenge this. Isn’t the existence of species-change less fundamental than common descent (i.e. the notion that all organisms are literally blood-relatives of each other, however distant)?

Wouldn’t common descent better capture the profoundest insight of Darwin’s intellectual contribution?