I attended the 2008 Western Evolutionary Biologists (WEB) conference on Sunday, sponsored by NERE. The winner of this year's Western Evolutionary Biologist of the Year (WEBY) was Kevin Padian of UC-Berkeley, in recognition of his many accomplishments in research and outreach in evolutionary biology. Kevin delivered a fun WEBY address, that mentioned his recent research briefly, and also discussed how evolutionists might better communicate with the public. In terms of bettering the abysmal anti-evolution statistics in the USA, Kevin thinks we shouldn't really focus much on the fundamentalists (who in my words are brain washed beyond rescue). Rather we should focus on a huge middle ground of people who may not understand the vast weight of evidence for evolution, and therefore have doubts, owing in large part to the anti-evolution propaganda machine that exists here. One of the topics Kevin brought up, which struck a chord in me because I just mentioned this in my Macroevolution class recently, is the difference between colloquial usage of words, and the meaning of those words in the scientific community.
Language and words, just like species and genes, evolve. Languages have been used to build phylogenetic trees to test hypotheses of human migration, and the meanings and relative usage of words often shift, sometimes radically, over time. An interesting example of this is what I've seen as a rather recent upsurge in colloquial use of the word "random". In fact, this "evolution of random" may have implications for how people understand the "random of evolution", the meaning of the word random in the context of natural selection.
Evolution of Random
In his best California-surfer-valley-girl accent, Padian illustrated current colloquial usage of the word random, "I, like, met this random guy in the mall the other day who...." (I actually can't remember the exact line Kevin used, but it was something like that). Kevin also defined current usage of random as identifying a non-sequitur, something that doesn't follow. I've certainly noticed this type of usage, and it seems to have surged tremendously in the past 5 years or so (perhaps because that is when I moved to California?) I've also thought of the colloquial use of random as meaning "unexpected", or even "unknown". For example, a "random" guy at the mall means to me that the speaker doesn't know the person. It also means that the reason the person was there is unimportant to the story, or unknown to the speaker. These colloquial meanings of random are quite different from statistical meanings, which is how I often think of its use in evolution.
Random of evolution
When I use the word random, I use the statistical meaning. Statistical randomness might mean that one possible outcome usually has an equal chance of being observed compared to another defined possibility. This is quite different than the colloquial usage that I mentioned above. A "random guy at the mall", according to the meaning often implied, does not include someone known to the speaker. So the speaker's dad is not included in the set of possibilities, which might be considered a decidedly non-random subset of all possible people, based on the statistical definition I presented above.
Kevin also made an interesting analogy, illustrating yet another subtlety in the statistical meaning of random. House fires may be modeled as random events. Given no prior information about one's house, there is a given probability that one's house will burn down. But if we have more information, we find out that most fires are caused by smoking in bed and arson. So, if a person is not a smoker, and has no pyromanical enemies, the chance of their house burning down is much lower than "average". Here, we are defining a random event (house fire) as stochastic, happening "by chance", yet recognizing that specific factors can alter the probability in specific instances. As Padian mentioned, if John Doe has an angry ex-spouse looking to torch the house lost in a divorce, the probability of Doe's house burning down goes up.
Given these sometimes subtly different usages of the word random, it's no wonder that sometimes people misunderstand natural selection, which has a "random" element. For natural selection to act, heritable variation must be introduced into a population. Evolutionists conceive of mutations as random events, and just as a certain prior knowledge of house fire risk can guide our estimation of probabilities, so can our prior knowledge of mutation. For example, flies exposed to UV light show a much increased rate of mutation. We might expect whole genome duplication events to be rarer than some other forms of mutation. But we don't mean that a mutation is a non-sequitur, or that a mutation is (necessarily) unknown to us or unspecified. And this is just a part of the entire process of natural selection!
Kevin's point in this is that we must be very careful about language. We must consider who is our audience, and what is their exposure and typical usage of different words. We must define clearly what we mean, and how our usage might differ from theirs. None of this is easy. As I grade exams, I see that understanding natural selection can be difficult for people; a difficulty probably caused by one random misunderstanding after another.