From pangens to polynucleotides: the evolution of ideas on the mechanism of biological replication.

Abstract

PERSPECTIVES IN BIOLOGT AND MEDICINE Volume 19 · Number ·/ · Summer 1976 FROM PANGENS TO POLYNUCLEOTIDES: THE EVOLUTION OF IDEAS ON THE MECHANISM OF BIOLOGICAL REPLICATION* M. R. POLLOCKi Many people here, and assuredly anyone who has worked as an editor ofscientific publications, will know what I mean when I say that the word "clearly" is a swindle. It means that the author is unable to provide any good evidence in support of what he is about to say and hopes to get away with it by persuading his readers that it is so obvious, or so universally accepted, that it is a waste of time to go over the arguments. In other words it means "wnclearly." There are a number of other similar trick words or phrases. For instance, "If I might say so" means "I am determined to say so, unconditionally , whether you like it or not." "With respect" means "with no respect—for a view I detest." "It goes without saying" means "I am now going to say something which I am unable—or unwilling—to support by any sort of rationale," and so on. People have a tendency to say the exact opposite of what they mean—or perhaps I ought to say, should mean. And this tendency, I believe, is especially pronounced when they are puzzled and unable to understand something properly. When they are at a loss for an explanation , they often pretend that no explanation is necessary or that it has already been provided. The less people know about something, the more dogmatic they become. As Bertrand Russell is quoted, "It is an odd fact that subjective certainty is inversely proportional to objective certainty " [I]. Yet human beings are always seeking explanations for things. For ?The Huxley Lecture, delivered at the University of Birmingham, Birmingham, England on March 6, 1975. tProfessor of Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland. Perspectives in Biology and Medicine · Summer 1976 I 455 most people this seems primarily to involve the description of puzzling or unfamiliar situations in familiar terms. (But, for a different approach, see Stephen Toulmin [2].) By this means they feel more at ease in confronting the situation. What is felt to be familiar depends, of course, on current fashion and the extent of previous experience. The types of explanations acceptable at any particular period, or within any particular community, for what is essentially the same situation thus vary enormously. And scientists are not all that different from other people in this respect. For them an explanation is a reanalysis ofa phenomenon in different terms and other elements, such that a greater degree of intellectual and emotional satisfaction is attained. This may involve a number of factors—reductive analysis in terms of smaller elements, conformation with other previously accepted explanations , predictive power and pragmatical usefulness, the integration of previously separate situations into a single more general conceptual system , and above all, a reinterpretation in a manner more appropriate to current forms of thinking, even though this may, somewhat paradoxically , involve the introduction of new terms and new concepts. This is unlikely to occur unless the new approach can be fitted into the scheme of what has been referred to by Stent as "canonical knowledge." Another factor, more difficult to recognise and define, seems sometimes to involve a sort of pushing away of a problem: a reanalysis or redescription in terms which do not shriek for immediate interpretation (often because the tools are not present for such interpretation). The effect of such a process of what is felt at the time to be an explanation —or a more satisfactory explanation—often strikes later generations of scientists as simply the substitution of one vague, largely meaningless statement for another. The evolution of knowledge has not been from a primitive state of puzzlement to one of greater and greater understanding, ever approximating nearer and nearer to the absolute truth, although some would still try to maintain that this is so. But explanation sometimes seems to be little more than a second statement, such as "it is God's will" in answer to a query about why (for example) it has not rained for 8 months; or the well-known...