wallace@ucbvax.ARPA (David E. Wallace) (05/18/85)
In article <1083@uwmacc.UUCP> dubois@uwmacc.UUCP (A Ray Miller) writes: > ... > >Personal comment here. Why don't you evolutionists all move your homes over a >toxic waste dump? Mutations are how you claim evolution progresses; increasing >the mutation rate should increase the rate of evolution. Should we disband the >EPA? I'd really like an answer to this question from any evolutionist who >doesn't consume heavy metals with his scrambled eggs for breakfast. > >A. Ray Miller >Univ Illinois Ok, I'll give it a shot. Point number 1: Increasing the mutation rate won't necessarily increase the rate of evolution. Since evolution depends on the interaction of natural selection with mutations, increasing the mutation rate by itself may or may not increase the rate of evolution, just as increasing the number of programmers assigned to a job may or may not increase the rate at which the job gets done (it depends on whether or not the variable increased had been the limiting factor, and on the interactions between factors). In the case of evolution, I would say the result depends on the amount of selective pressure on the species in question, on the amount of variation already present in the population, and on the previous mutation rate. If the species is well-adapted to a reasonably stable environment (selective pressure low), has a reasonable amount of variation already present, and a non-trivial existing mutation rate, increasing the mutation rate might not do diddley-squat to the rate at which the species evolves. However, it probably would increase the number of defectives born in each generation, which brings me to my second point. Point number 2: Even if increasing our mutation rate would increase the rate at which we evolve, that is not necessarily a morally desirable end. Evolution is a natural process, like gravity. As such, it is intrinsically amoral: neither right nor wrong, moral nor immoral in itself; it just is. It describes how things are, and how they have gotten to be that way, not the way things should be. That is a judgement that we must make, as thinking, feeling, moral beings. When gravity operates to hold the atmosphere about our planet, allowing us to breathe and live, we judge the result to be good. When gravity brings an aerial walkway crashing down, killing hundreds of innocent people below, we judge the result to be bad, a terrible tragedy. But it is the same force, the same law that operates in both cases. That force is neither good nor bad in itself; it is we who judge its results to be good or bad, based in large measure on how it affects us and our fellow human beings. So too it is with evolution. Because one of the many results of the evolution of life on this particular planet has been to produce us, we tend to regard this particular result as good, in our anthropocentric way. But this does not mean that all the results of evolution are to be judged as equally good or desirable. If a million less fit blades of grass perish in the process of evolving some new species of grass that is better adapted to an environment, no one of us much cares, since we do not tend to attribute moral value to the life of a blade of grass. But we do attribute moral value to the lives of human beings. If we were to increase our own mutation rate, it is quite possible that we would in fact evolve some new and potentially useful features (such as improved resistance to heavy metal poisoning, for example). But it is virtually certain that among the other consequences of this increased mutation rate would be an increase in the number of stillbirths and crippling birth defects. This is not a morally neutral consequence. I, and I think most other people, would regard the potential gain from an "increased rate of evolution" as not being worth such a terrible price. What's more, to take such a course would be to disregard the value of our most valuable resource -- our brains. Biological evolution is a rather chancy thing, after all. It tends to take a long time in human terms -- thousands or millions of years for many significant changes. While the general direction of change is predictable -- species evolve in the direction of greater adaptation to their environments -- the specific details are not. If we increased the concentration of heavy metals in our environment, we might evolve an increased resistance to heavy metal poisoning by itself, or we might get the resistance along with some undesirable side effects, such as decreased intelligence or lifespan, or we might just become extinct if we didn't evolve the resistance fast enough. Remember that one of the side effects of increased resistance to malaria is sickle-cell anemia in those offspring unfortunate enough to inherit a double dose of the gene in question. I'm not knocking biological evolution totally -- it's what got us here, wonderful brains and all. But now that we're here, we can do better than that to cope with our environment. Through cultural evolution, using our wonderful brains to develop and transmit culture, we can adapt our environment to us instead of the other way around. In my opinion, cultural evolution is one of the truly great innovations in the history of life on this planet, ranking right up there with the genetic code, multi-cellular structure, internal skeletons, air-breathing, and warm-bloodedness. For the first time, a species has been freed from many of the constraints of biological evolution. Whereas biological evolution takes millenia or eons to do its work, cultural evolution can occur in months, years, or decades. Just look at all the human race has accomplished -- good, bad, and indifferent -- in the past 5,000 years of recorded history, a bare instant in the history of life on earth. What's more, cultural evolution is more than just a speeded up version of biological evolution: it has the potential to overcome one of biological evolution's most fundamental limitations, the inability to plan for future changes in the environment. Biological evolution operates by adapting organisms to their immediate environment. Whether or not these adaptations help the organism survive if the environment changes drastically is pretty much a matter of dumb luck. Some do, some don't. But we are not bound by this limitation in our cultural evolution: we can plan ahead, anticipate the future effects of present causes, and take action to head off those consequences we consider harmful. We don't do this perfectly, of course, and even when we can do this, that is no guarantee that we will. But even though we do it imperfectly, that's still better than a blind crapshoot. So given the environmental challenge of toxic wastes in the environment, we have two choices. We can sit tight and take our chances with the crapshoot, waiting for biological evolution to do its thing, hoping that it doesn't saddle us with too many nasty side effects, and that it happens soon enough to keep us all from joining the dinosaurs in that great extinction museum in the sky. Or we can use the brains that biological evolution gave us, and the cultural evolutionary software we're running on them to recognize the problem and take action, by removing the wastes from those parts of the environment where they can affect us, and by redesigning and redirecting as many of our cultural activities that generate such wastes as we can, thereby accomplishing the desired result (increased resistance to the threat of toxic wastes) more surely, more swiftly, and at a far lower cost in human lives and hopes. Morally and rationally, the choice is clear. So that is both why I'm not going to move over a toxic waste dump, and why we shouldn't disband the EPA. Two more things: a moral and a comment. The moral: Increasing the human mutation rate to facilitate further evolution is like jumping off a tall building to facilitate the action of gravity. The comment: A variation of the above argument is the basis for refutation of Social Darwinists and others who believe that because biological evolution works that way, society should too. David E. Wallace (...!ucbvax!wallace wallace@Berkeley)