Letters to and from the Editor

LETTERS TO AND FROM THE EDITOR Dear Sir: Mankind Evolving—A Rejoinder A.J. Toynbee, the hbtorian, wrote that "it b more profitable to try to learn from one's critics than to try to fight them." Thb is the spirit in which 1 like to treat SirJulian Huxley 's critique of my book Mankind Evolving (Perspect. Biol. Med., 6:144, 1962). He charges that I have "mbunderstood some ofthe basic ideas ofmodem evolution theory." What are these ideas? He reproaches me for having failed to point out "that the whole of evolution, including psychosocial evolution, b a directional and cybernetic process, involving constant feedback between past results and future course." I have pointed thb out in the very first paragraph on page 1, and in several places ebewhere in the book! There seems little point ofbelaboring the trubm that the organic evolution has not been entirely haphazard, since thb follows from the fact that it has produced man, and the world b no longer populated by only amoebae and simple viruses. The exbtence of a feedback between the biological and the cultural evolutions of mankind is, in fact, the central thesb ofmy book, as stated quite explicitly on page 18. Surely, SirJulian does not contend that evolution is orthogenetic, directed towards producing man or any other fixed goal. Extinction of most phylogenetic lines shows that the feedback does not always operate to the benefit ofthe evolving group. There is no disagreement between us on thb matter. But we differ on what is the fitness which the action ofnatural selection promotes. The concepts offitness and ofnatural selection have changed greatly since Darwin, as I have tried to explain in Chapters 6, 11 and 12 ofmy book. I am not in favor ofcluttering the literature with a mass ofnew terms, although the authorship ofsuch terms is the main claim to fame of some scientific writers. Sir Julian complains that "the idea that 'fitness' b to be defined solely in terms ofthe capacity to leave more descendants has been fobted onto general biology by the students ofpopulation genetics, which happens to be one of the avant-gardesubjects in contemporarybiology." Here I mustdisappoint him—population genetics has "fobted" thb idea quite firmly. Darwinian fitness b reproductive fitness, but by maintaining or increasing thb fitness, natural selection usually, though not always and not necessarily, maintains or improves the general adaptedness ofthe organbm in the environments which the latter inhabits. By so doing, natural selection serves as the mechanbm which makes the feedback processes ofwhich we spoke above possible. Defining the fitness ofa genotype as its contribution to the gene pool ofthe next generation relative to the contributions of other genotypes makes thb concept operationally meaningful and 275 susceptible ofmeasurement. What SirJulian calb "the common assumption that civilized man b no longer exposed to the action ofnatural selection" must, indeed, be denied, and, fortunately, thb assumption is becoming less "common." It b not the question ofwhether natural selection is working on man, but whether it is doing what we would like it to do. SirJulian abo reproaches me for not having dbcussed in my book several topics which he thinks Ishould have dbcussed. Some ofthese reproaches are valid, and I may heed them on a future occasion. I cannot conclude thb comment better than by quoting another suggestion ofToynbee, based on hb extensivepractice ofbeing a reviewer and a reviewed: "When I am playing the role ofa reviewer I find it a useful rule to remind myselfof the indubitable truth that a reviewer inevitably reviews himself, too, in the act ofreviewing the author whose book lies on his dissecting table." Theodosius Dobzhansky The Rockefeller Institute New York 21, New York Dear Sm: Last week I received the first bsue ofmy subscription to perspectives in biology and medicine. I was surprised and irritated by what amounts to a dbcriminatory practice I certainly had not expected to see in yourjournal. I refer to the use ofthe M.D. degree after the names ofmedical people and the absence ofdegrees after the names ofall others. Certainly others have degrees which abo tend to identify and describe, and which indicate some manner ofprofessional standing. In ajournai ofthb type, so obviously a...