The working scientist who entertains the notion of writing a history of his discipline must do so with diffidence and no little trepidation. While he may know more of the facts and scientific interrelationships within his specialty than does the professional historian, nothing in his training or experience has prepared him to deal in the special currencies so familiar to the historian in general, and to the historian of science in particular. If he is to write more than a mere encyclopedia of names, dates, places, and facts – an unappealing venture – then he must deal with such unfamiliar concepts as the sociology and epistemology of science, cultural relativism, etc. Such recondite ideas rarely enter into the formal training of the biomedical scientist, and never into his scientific practice. Indeed, if he considers such concepts at all, it is probably with suspicion and perhaps disdain, relegating them to that special limbo which he maintains for the “impure” social sciences, firm in the conviction that his is a dependably precise “pure” science.

But this is not the most serious challenge to the practicing scientist-turned-historian. Assuming that he has overcome the typical scientist's feeling that Santayana's maxim “Those who cannot remember the past are condemned to repeat it” applies only to politicians, diplomats, and economists, he has a yet more difficult preparatory task before him. This involves nothing less than a re-examination and perhaps rejection of some of his most cherished beliefs – beliefs rarely stated explicitly, but so implicit in all of the scientist's training and education and so permeating his environment as to have become almost the unwritten rules of the game.

The first of the beliefs to be re-examined is that of the continuity of scientific development. By this I mean that most mature scientists, and all students and members of the novitiate, tend to suppose that all that has gone before in a field was somehow aimed logically at providing the base for current work in that field. Thus, there is a general view that the history of a discipline involves an almost inexorable progression of facts and theories leading in a straight and unbroken line to our own present view of the workings of nature. (Historians refer to this as “Whig history,”1 and condemn its practice.) Put in other terms, the scientist is tempted to regard the development of his science in much the same way that most of us seem to regard the origin of species – as a sort of melioristic evolution, following a preordained path toward the acme of perfection and logical unity: in the one case man, and in the other our present science.

But this is not really surprising, when we consider how most science is practiced and reported, and especially how scientists are trained. In the first instance, the scientist chooses a problem to work on that could scarcely be justified as other than the next logical step in the progress of his discipline – i.e., the next obvious question to be asked and problem to be solved. Then, having successfully seen the research to its conclusion, he submits the work to the scientific literature (the unsuccessful excursions generally going unreported). Now, for a variety of reasons, including ego, space limitations, and the implicit cultural view of how science ought to function, our author prepares his manuscript so that not only is the work presented as internally logical and the result of an ordered sequence from start to finish, but the background introduction and its supporting references from past literature are also carefully chosen to demonstrate that this work was eminently justified in its choice, and in fact was the next obvious step forward in a well-ordered history. Each communication in the scientific literature thus contributes modestly and subtly, but cumulatively, to a revision of the reader's understanding of the history of his discipline.2

There is, however, a far greater force in science which operates to impose an order and continuity on its history, manifested not only by an influence on the types of problems deemed worthy of pursuit, but more importantly in the way in which young scientists are educated. There is in any scientific discipline, and there ought to be, a priesthood of the elite. These are the guardians of the scientific temple in which resides the current set of received wisdoms. These are the trend-setters and the arbiters of contemporary scientific values. They are also, not coincidently, the principal writers of textbooks and the most sought-after lecturers, as well as the principal researchers in whose laboratories young people serve their scientific apprenticeships. They are, in brief, the strongest and most vocal adherents of what Thomas Kuhn, in his provocative book The Structure of Scientific Revolution,3 has called “the current paradigm.” In Kuhn's usage, a paradigm in any field is the current model system and the accepted body of theories, rules, and technics that guide the thinking and determine the problems within that field. Kuhn points out that when a change in paradigm occurs within a discipline (he insists that this is inevitably the result of an abrupt revolution), the textbooks must be rewritten to reflect the new wisdom. This invariably involves a revision in the interpretation of what went before, so that the new paradigm can be shown to be fully justified as a step forward in scientific progress, and worthy in all respects to command the attention of the current community of scholars. Since the object of a text is pedagogy, the facts many and the concepts complex, what went before must necessarily be winnowed, abstracted, and digested, in order to provide the student with what is required to follow in the illustrious footsteps of the current priests. Therefore, the modest history that is included in most texts, and the routine appeals to the idols and heroes of earlier times, are more often than not subconsciously slanted to help justify the current paradigm and its proponents; they serve to reinforce the impression of a uniform continuity of scientific development. Assuming that one is a reputable member of a current scientific community, and thus a subscriber to the current paradigm, the scientist-turned-historian must be especially on guard not to contribute also to a revisionist history of the field. One might then be rightly accused of presentism,4 the interpretation of yesterday's events in today's more modern terms and context.

The second of the beliefs that require re-examination – one also nurtured by our traditional system of scientific pedagogy – is that of the logic of scientific development. We have already seen that the investigator justifies the choice of a research problem (not only to scientific peers but also to the sources of financial support) by demonstrating its logic within the context of the accepted paradigm. This is, of course, eminently reasonable, since a paradigm lacking in inner logic (i.e., unable to define the nature of the problems to be asked within its context or to assimilate the results obtained) would scarcely merit support. But the existence of a logical order of development during the limited lifetime of a paradigm is often extended to imply an overall logical development of the entire scientific discipline. Moreover, the concept examined above of a smoothly continuous maturation of a science implies also that its progression has been logical – the step-by-step movement of fact and theory from A to B to C, as the Secrets of Nature are unfolded and Ultimate Truth is approached. Indeed, to accuse science of illogic in its development would, to many, imply the absence of a coherent unity underlying the object of science's quest – the description and understanding of the physical world.

And yet, there is so much that is discontinuous and illogical in the development of any science. On the level of the individual research activity, much attention is paid to the beauty and strength of that eminently logical process, the Inductive Scientific Method. The working scientist, however, who thinks about the course of his own research must wonder sometimes whether the description is apt. One of the few biologists who reflected aloud on this problem was Sir Peter Medawar, in his Jayne Lectures before the American Philosophical Society. Following the lead of philosopher Karl Popper,5 Medawar6 challenges the popular notion: