Meyer and Keas caution people about answering questions about evolution until the term is clearly defined.
Here are their 6 meanings of the word:
- Evolution as Change Over Time
- Evolution as Gene Frequency Change
- Evolution as Limited Common Descent
- Evolution as a Mechanism that Produces Limited Change or Descent with Modification
- Evolution as Universal Common Descent
- Evolution as the “Blind Watchmaker” Thesis
Here is one that everyone accepts:
2. Evolution as Gene Frequency Change
Population geneticists study changes in the frequencies of alleles in gene pools. This very specific sense of evolution, though not without theoretical significance, is closely tied to a large collection of precise observations. The melanism studies of peppered moths, though currently contested, are among the most celebrated examples of such studies in microevolution. For the geneticist, gene frequency change is “evolution in action.”
And one that is controversial:
6. Evolution as the “Blind Watchmaker” Thesis
The “blind watchmaker” thesis, to appropriate Richard Dawkins’s clever term, stands for the Darwinian idea that all new living forms arose as the product of unguided, purposeless, material mechanisms, chiefly natural selection acting on random variation or mutation. Evolution in this sense implies that the Darwinian mechanism of natural selection acting on random variations (and other equally naturalistic processes) completely suffices to explain the origin of novel biological forms and the appearance of design in complex organisms. Although Darwinists and neo-Darwinists admit that living organisms appear designed for a purpose, they insist that such “design” is only apparent, not real, precisely because they also affirm the complete sufficiency of unintelligent natural mechanisms (that can mimic the activity of a designing intelligence) of morphogenesis. In Darwinism, the variation/selection mechanism functions as a kind of “designer substitute.” As Dawkins summarizes the blind watchmaker thesis: “Natural selection, the blind, unconscious, automatic process which Darwin discovered and which we now know is the explanation for the existence and apparently purposeful form of all life, has no purpose in mind. It has no mind and no mind’s eye.”
For discussion purposes, I accept 1-4, which I think are consistent with the evidence. I deny 5 and 6 because they are inconsistent with the evidence.
It’s a good article to read to prepare yourself to discuss this with someone who is antagonistic to design. They may offer evidence for one definition of evolution that everyone accepts, then take it to be proof of a much more controversial definition of evolution. You have to get the definition clear first.
One last piece of advice. If you ever get asked this “do you believe in evolution” question – say, by a secular leftist anxious to label you as a moron – then you might consider going on the offensive, using this list of alternate science-related questions that actually affect public policy from David Harsanyi. Put your questioner on the defensive.