Recently, I found myself greatly amused by a particular Doonesbury strip illustrating the problems with the creationist assertions. Deciding to share my amusements with those who cohabit the dormitory in which I spend my sleeping hours, I printed a copy and posted it on my door. A few days later, I found that my posting had been modified to include a strange response:
"Evolution is a complete change of species: fish to bird. [The adaptation of pathogens to drugs] is called natural selection. Get the facts straight, stud."
This statement is simply false. Evolution can include complete changes of species, but not in any sort of sudden sense. In order, then, for a complete change of species to occur by evolution, there must be intermediate steps that are incremental in nature. Thus, these too should be considered part of evolution as any theory of evolution predicts their existence.
Interestingly, this response did not actually "debate" anything, but seems to have sought to distract other readers of my door with a semantic sleight of hand. I have posted to other forums on this tactic, but I feel strongly enough as to do so again on this forum. Here, our friendly neighborhood linguistic charlatan, whether consciously or not, has acted to confuse the method with the effect. Evolution can happen by many different methods, of which natural selection is but one. We can exact a change in a species through other methods, such as artificial selection practiced in the breeding of domesticated animals, resulting in an evolution of that species. At its most basic, to say that evolution exists is to say no more than that the world's zoology is not constant with respect to time and space. This notion can be experimentally shown by an examination of any number of datasets, including fossil records showing a set of species not found on modern-day Earth.
The more controversial notion is that of natural selection, the proposed method by which species evolve. (It should be noted that this is technically not correct -- species do not evolve as a direct result of natural selection, but rather, genetic patterns evolve with species as hosts. For our purposes here, however, the two models are in close enough agreement that we need not belabor the point further than to point an interested reader to Richard Dawkins.)This can be observed directly on a microscopic scale, but the allegation by the creationist apologists is that the lack of direct observation for macroscopic natural selection precludes the proposal that macroscopic natural selection is responsible for evolution from being useful or worthy of consideration. Of course, by similar criteria we are left with no viable explanation of the observations alluded to above. Creationism is no more able to produce evidence from the depths of time long past, and in fact lacks any analogous data to that of microscopic natural selection, which serves to suggest that the principles are sound and should hold at other scales. Thus, the whole trickery of trying to recast the debate into terms of an emotionally charged term and then seeking to redefine the term in a straw man argument is seen to be a callous attempt to change the universe by changing popular opinion.
What would be the effect if our delightful correspondent had succeeded in convincing all of his readers that evolution is a sham? Would the universe suddenly stop evolving? Would TB drugs of yesteryear suddenly become effective again? No. The universe would not even slow down in its continual process of change, despite our kicking and screaming, and our denial of overwhelming evidence. Such intellectual dishonesty gets us no where, as it ultimately divorces us from the world around us and impairs our ability to make rational judgments.