By definition, everything that changes over time has its own history, such as universes, countries, dynasties, art and philosophy, and ideas.Science, too, has undergone constant historical change since its origins in mythology and early philosophy, and science is therefore a natural proposition for historians.The essence of science lies in the ongoing, never-ending process of answering questions that people ask to understand the world they live in.The history of science was first a history of the problems it faced and its solution (or attempt to solve) them.Not only that, but the history of science is the history of the development of the basic principles that constitute the conceptual structure of science.Because many important scientific controversies of past ages are often imported into modern science and continue to be debated, the significance of many current controversies cannot be fully appreciated unless the history of these controversies is known.

Like science itself, written history needs constant revision.Misinterpretations by early authors are likely to end up as myths, passed down from generation to generation in the belief that they are true.Therefore, I am particularly focused on exposing and dispelling as many myths as possible, while hoping not to create new myths.The main reason why history books are constantly revised is that they can only reflect the knowledge at that time at any given time; French science tends to be mathematical and rational?Why did natural theology dominate British science about 75 years longer than continental science?Some people say that Darwin's theory of natural selection is a product of the industrial revolution, so how much influence did the latter have on the former?

Although the historian of biology does not take this approach, if he is to determine the causes of new concepts, he must carefully study the cultural and intellectual background of the scientists who developed them.This is obviously important for this book, because one of my main purposes is to explore the reasons for the evolution of biological theory, which must ask the following questions: New things ignored by generations?Why can he abandon the traditional view and propose a new explanation?Where did he get the inspiration to take a new approach? Most early histories of science, especially professional histories, were written by working scientists who took for granted that the dynamics of change in science came from within the field itself ("internal" influences, internal causes) .Later, when the history of science became more professionalized or specialized, historians and sociologists began to study and analyze the development of scientific thought, and they tended to focus on the general intellectual, cultural, and social context of the time ("outside" influences , external cause).No one wants to doubt the existence of these two influences, yet there is much disagreement about their relative importance, especially when it comes to specific developments such as Darwin's theory of natural selection.

Even sometimes it is difficult to distinguish internal and external factors. The "Great Chains of Nature" ("Nature's Ladder") is a philosophical concept that clearly influenced the conceptualization of Lamarck and other early evolutionists. Aristotle, however, was based on empirical observations of living things On the other hand, the ideology or concept generally accepted by people is one of the indisputable external causes. For hundreds of years, the dogma of Christian creation and the arguments deduced by natural theology have dominated Biological thinking. Essentialism, derived from Plato, is another idea of ​​omnipotence that has had a profound impact on people. Interestingly, it was rejected by Darwin mainly because of animal breeding The observations of scientists and taxonomists, that is to say, are due to external causes.

External causes do not have to come from religion, philosophy, cultural life or politics, they can also come from other sciences (in the case of biology).The extreme physicalism (including determinism and extreme reductionism) widely popular in the West after the scientific revolution has seriously affected the establishment of biological theories for hundreds of years.Looking back now, most of the above-mentioned influences are not conducive to the formation of theories.Another example is the scholastic logic that dominated taxonomic methods from the time of Cisapino to Linnaeus.These and many other examples which may be added clearly show the importance of external influences in the establishment of biological theories.In the following chapters, we will conduct a detailed analysis of these effects.

External factors influence science in two quite different ways.They either affect the overall level of scientific activities in a certain area and at a certain time; or they affect or even lead to the emergence of certain scientific theories.It is very important to distinguish this point. In the past, the two aspects were often confused, which caused a lot of debate on the issue of which is more important, the external cause or the internal cause. The influence of environmental conditions on the level of scientific activity has been recognized as early as the first history of science.People have been wondering why the Greeks were so interested in scientific questions, why science was revived during the Renaissance, and what influence did Protestantism have on science (Menton, 1938)? Why did science flourish to such an extent in Germany in the 19th century?Important external causes can sometimes be specified, for example (as Merz, 1896-1914 once pointed out), the replacement of Latin by German at the University of Halle (Germany) in 1694, the founding of a university in Göttingen in 1737, in which "Science" courses occupy an important place in universities.Various changes in social institutions, including the founding of the Royal Society, political events such as the war and the launch of the Soviet Sputnik, as well as technological and engineering demands have had either stimulating or depressing effects on the level of scientific activity.Even so, the extent to which these external causes support or suppress a particular scientific theory remains a debated question.

Sir Acton reminded historians more than a hundred years ago: "Study history, not epoch." This advice applies especially to the history of biology, where scientific questions remain unresolved for a long time. Many of the famous polemics of the nineteenth and early twentieth centuries dealt with issues that were known as early as Aristotle's time.These debates have continued from generation to generation, century after century.They are processes rather than events, and thus can only be fully understood if they are discussed as history.As R. G. Collingwood said of history (1939:98): "It is concerned not with events but with processes. Processes are states of affairs with no beginning and no end, they can only be transformed into each other." This must be emphasized , especially in the face of the static view of the logical positivists.Positivists believe that the logical structure is the real problem of science: "Philosophy of science for them is mainly a careful and exhaustive analysis of the logical structure and conceptual problems of contemporary science" (Laudan, 1968).In fact, most scientific problems are better understood by studying their history than by studying their logic.However, it must be noted that interrogative history is not a substitute for chronicle, the two are complementary to each other.

Solving scientific problems is never easy.In interrogative history, the history is primarily concerned with attempts and efforts to solve problems such as the nature of fertilization and the directional factors of evolution.Present not only the history of successful attempts to solve these problems, but also the history of unsuccessful attempts.In approaching major controversies in biology, focus on analyzing the ideologies (or beliefs) on the opposing side and the specific evidence used to support their opposing theories.In interrogative history the focus is on the professional scientist and his world of ideas.What were the scientific problems of his day?What concepts and technical means does he possess in attempting to solve the problem?What methods are available to him?What prevailing ideas in his day guided his research and influenced his decisions?Questions of this nature dominate the study of interrogative history.

I employ this interrogative approach in this book.Readers should realize that this is not a traditional history of science.Because of its focus on the history of scientific issues and concepts, it necessarily neglects the biographical and sociological aspects of the history of biology.It should therefore be read in conjunction with a general history of biology (eg Nordenskiold, ed., 1926), a Biographical Dictionary of Scientists, and any available histories of biology-related disciplines.Because I am a biologist, I am better suited to write a history of biological issues and ideas than to write a biographical and social history.

The essence of interrogative history is to ask why.Why was the theory of natural selection developed in England alone, and in fact four separate developments?Why did real population genetics rise in Russia?Why is Bateson's interpretation of heredity almost entirely wrong?Why did Courens contribute so little to the major advances in genetics from 1900 onwards by spreading his energies over various peripheral problems?Why did the Morgan school spend so much energy in so many years consolidating the well-established chromosome theory of heredity without finding another way?Why are de Vry and Johnson so much more comfortable applying their findings in orthodox genetics than in evolution?Answering these questions requires the collection and scrutiny of vast amounts of data and evidence, and as a result, new insights are bound to emerge even when the questions in question turn out to be inconclusive.The answer to the why question, while inevitably somewhat speculative and subjective, forces one to organize the results of the research, and to constantly review one's conclusions in a way consistent with speculative reasoning. The legitimacy of the "why" question is now firmly established in scientific research, especially in evolutionary biology, much less should it be a problem in the writing of history.At worst, the kind of exhaustive analysis necessary for a why question might conclude that the assumptions underlying the question are wrong.Even so, it raises our awareness.

Throughout the book I have analyzed each problem in as much detail as possible, breaking down the jumble of heterogeneous doctrines and concepts into their individual components.Not all historians realize how complex many biological concepts are—indeed, how complex the structure of biology as a whole is.Thus, some extremely confusing statements about the history of biology are the result of the authors' failure to understand that biology is divided into two categories of biology, functional causes and evolutionary causes.In the same way, anyone who writes about "Darwin's theory of evolution" in general without separating out the theories of gradual evolution, common origin, the formation of species, and the mechanism of natural selection shows that he is not competent for this task. writing task.Most of the important theories in biology were such hybrids when they were first proposed.Their history and influence cannot be understood unless their components are separated and studied individually.Sometimes they belong to very different ideological systems. I am convinced that the development of biological thought cannot be understood unless one understands its thought-structure.I have therefore endeavored to present biological insights and concepts in considerable detail.This is especially necessary when discussing diversity (Part 1 of this book), since so far no other book has adequately addressed diversity and lacked a conceptual structure for it.I realized that my book would run into the danger that some critical reviewer would exclaim, "It's just a biology textbook, only in historical order!" .I think this may be the inevitable fate of a questioning history of biology.Perhaps the greatest difficulty of any book on the history of biological concepts is that it has to deal with a long history of scientific controversies.Many contemporary scientific controversies originate generations, even centuries, and some indeed go all the way back to Greek times.A more or less "timeless" account of such questions would be better than a chronological approach. I have tried to treat each section of the book (diversity, evolution, inheritance) as a stand-alone unit.Each of the individual questions is similarly separated in the three parts.The result of this treatment is a certain degree of repetition and redundancy, because there are so many cross-linkages between different themes, and some parts of each theme pass through the same sequence and time-dependent cultural background.I have tried to strike a balance between unavoidable repetition at a given length and cross references to previous and subsequent chapters for the convenience of the reader. " A well-known Soviet Marxist theorist once referred to my work as "completely dialectical materialism".I'm not a Marxist, and I don't know the latest definition of dialectical materialism, but I do admit that I bear some of the anti-reductionist views Engels articulated in "Anti-Dühring"; Geer's "thesis-antithesis-synthesis" three-stage formula.Furthermore, I also believe that an antithesis is most easily elicited when the thesis is explicitly stated.Only through the irreconcilable direct opposition between the thesis and the antithesis can the problem be solved most easily, and the final synthesis can be achieved most quickly.Many examples of this can be found in the history of science. It is this insight that has guided me in writing this book.Whenever possible I have attempted to synthesize opposing views (unless one of them is manifestly false).In unresolvable situations I have, if I think fit, set forth opposing views in definite, sometimes almost partial terms, in order to provoke a reply.Because I hate beating around the bush, I am sometimes seen as assertive.But I think it's a mistake to see my attitude that way.It has never been my attitude to be an assertive person who insists on being infallible despite evidence to the contrary.Honestly, I'm still proud of the fact that I've changed my mind on a number of occasions.All in all, it is true that my strategy is to make a thoroughly definite statement.Whether this counts as a mistake in the free exchange of scientific ideas can be debated.I myself think that scientific problems can be solved more quickly and completely by this than by taking a cautious and cautious attitude of sitting on the fence.I agree with Passmore (1965): history (books) should be polemical.Such a history will inspire contradictions and prompt readers to come forward with rebuttals.Synthesis of ideas will be accelerated through a dialectical process.Unanimous acceptance of a point of view should not be confused with subjectivity. The traditional advice to the historian is always to remain strictly objective.The eminent historian Leopold von Ranke articulated this ideal clearly.He said historians should "reveal what the past really was".In his view, history is the exact reconstruction of a series of events in the past.Such objectivity is entirely appropriate when one is trying to answer the who, what, when, and where questions, but it must be pointed out that the historian is subjective even in stating facts, for he is making decisions about trade-offs, choices, Facts, and the value criteria by which they relate to each other, are selective. Subjectivity can arise at every stage of the history book writing process.This is especially true when asking why and seeking explanations, which is what interrogative history requires.It cannot be explained without using one's own judgment, which is inevitably subjective.A subjective statement is often more exciting than a serious objective statement because it is more revealing. To what extent is subjectivity permissible, and under what circumstances does subjectivity become prejudice?This can be illustrated with an example. Radl (1907-08) had a considerable degree of prejudice against Darwinism, so that he could not properly explain Darwinism, which is obviously too much.Subjectivity can easily turn into prejudice whenever previous generations of scientists are judged.In such cases historians either go to one extreme or to the other.They either take a strict retrospective approach and evaluate the past completely according to modern knowledge and understanding;In my opinion, neither of these approaches is desirable. A better approach is to use the best of both worlds.This begins with an attempt to reproduce the intellectual and cultural background as faithfully as possible, but it is not appropriate to treat past debates strictly in accordance with the cultural knowledge that existed at the time.This would leave these disputes intact, as cloudy and unresolved as they were when they occurred.Another attitude is that modern knowledge should be used if it is useful in understanding past dilemmas.Only in this way can we clearly understand the reasons for the dispute and the key to the unresolved dispute.Controversy arises from ambiguity in semantics (for example, the same word is used to express different meanings)?Inconsistent concepts (such as essentialism and population theory)?Or is it due to a blatant mistake (such as confusing ultimate and immediate causes)?The use of modern knowledge in the analysis of both pros and cons is particularly illuminating in the study of past historical controversies. Semantic problems are particularly annoying because they often go unnoticed, for example the Greeks at the time had very little specialized vocabulary and often used one word to describe different things or concepts.Both Plato and Aristotle use the word eidos (and at least Aristotle uses it in several different senses!), but the main sense of the word is completely different in both of their usages. different.Plato was an essentialist, and Aristotle was an essentialist only to a certain extent.Aristotle occasionally used the word genos as a collective noun (equivalent to what taxonomists refer to as a genus), but often used it to denote a species.After Aristotle was valued again in the late Middle Ages, his works were also translated into Latin and Western European languages. The vocabulary he originally used could only be translated with the "equivalent" words contained in the medieval dictionary.Such misleading translations have had a detrimental effect on our understanding of Aristotle's thought.There are some modern writers who have boldly adopted modern vocabulary to reveal Aristotle's thought, and I think Aristotle would be happy to use these words if he were alive today.I also recall that Delbruck used the term "genetic program" to illustrate the idea of ​​Aristotle, who used the word eidos to mean individual development.Likewise, when Aristotle discusses goal orientation governed by eidos (programs), the term teleonomy should be used instead of teleology.This is not an anachronism, but simply a way of making sense of the minds of ancient writers using a set of terms that modern readers agree upon. However, it is very inappropriate to use modern hindsight to evaluate value.Lamarck, for example, if judged by the facts he knew at the time and the prevailing beliefs of the time, was never quite as good-for-nothing as the learned men of selectionism and Mendelian genetics believe. "The idiom whig internretation of history was first coined by the historian Herbert Butterfield to refer to the habit of some British constitutional historians to regard the Constitution as a progressive extension of the rights of man. , during which the "forward-looking" Liberals and the "backward-looking" Conservatives continued to struggle. Later Butterfield used the word whiggish (whiggish) to describe such a history of science, that is, each scientist is He is judged by the magnitude of his contribution to the establishment of our modern science; not by the intellectual background in which he worked at the time. That is to say, he is judged strictly in light of modern concepts. In this Whig history of science , ignoring all the concepts and contexts of problems upon which early scientists worked. The history of the biological sciences is full of such prejudiced Whig interpretations. Once a scientific debate has occurred, the views of the losing side are almost always distorted later by the victors.For example, the Linnaean school is against Buffon, the Cuvier school is against Lamarck, the Darwinian school is against Linnaeus, the Mendelian school is against biostatisticians, and so on.Historians of biology must try to make unbiased comments.There are some theories which have now been disproved (such as Lamarck's inheritance of acquired characters) which previously appeared to be so consistent with the known facts of the time that their founders should not be blamed for accepting them. to be blamed, even if the doctrines were later proven wrong.People who firmly believe in false doctrines almost always have plausible reasons for doing so.They try to emphasize certain aspects that are overlooked by their opponents.Preformationists, for example, attempted to emphasize something that was later revived in the name of genetic programming.Biostatisticians embraced Darwin's idea of ​​gradual evolution as opposed to Mendelian catastrophism.In the two examples given above, right thinking and wrong thinking were intertwined, and wrong things were believed to be true.For my part, I tend to pay special attention to the underdogs (both doctrines and people) in an argument because they have often been treated unfairly, or at least improperly, in the past. The path of science is never a straight line.There are always competing theories, and at one time most of the attention may be directed toward an irrelevant problem, leading to a dead end.Developments like these are sometimes more indicative of the zeitgeist of a period than the linear progression of science.Unfortunately, due to the limited space of this book, it is impossible to fully discuss such developments.No history book can address every failure and every deviation.However, there are exceptions.Certain past historical failures or blunders accurately reflect aspects of contemporary thought that would otherwise be overlooked. Quinarianism proposed by MacLeay and Swainson is an example.After Darwin's publication, quinaryism was immediately eclipsed; it represented, however, a sincere effort to reconcile the apparently disorganized multiplicity of nature and the then prevailing belief in a "higher" order in nature. Find a compromise between beliefs.At the same time it reveals the tenacious influence of the ancient mythology of the time, which asserted that all order in the world is ultimately expressed in numbers.Though ill-conceived and short-lived, pentadism contributed to our understanding of the thinking of its time.The same holds true for almost any doctrine or school of thought in the past, even if they are no longer considered true.A historian's interests necessarily influence his decision as to which subjects should be dealt with at length, and which can be skimmed over.My own preference is Schuster, who said in Advances in Physics: "I prefer frank subjectivity, and be forewarned that my account (in this book) will necessarily be fragmentary and will be largely To a certain extent, some associations are based on my own point of view." Two classes of scholars with very different perspectives and backgrounds—historians and scientists—both claim the history of science as their profession.Due to differences in interests and abilities, their respective contributions also vary.Scientists are willing to choose issues for analysis and discussion that are quite different from those of historians and sociologists.For example, recently many evolutionists seldom mention H. Spencer when studying and discussing the theory of evolution.It is not unreasonable to snub Spencer in this way.Not only is Spencer's discourse muddled, but also because some of the ideas he embraced came from others and were outdated by the time he absorbed them.Some of the ideas borrowed by Spencer were so popular and influential at the time that they were unquestionably true to the average person.The point is that it is not his task for the historian-as-scientist to step into the realm of the sociologist.Biologists generally lack the ability to study social history.Conversely, it would be absurd to ask a social historian to provide an informed analysis of a scientific problem.The history of science draws knowledge, inspiration and methodological support from the two disciplines of science and history, and in turn contributes to science and history with its own research discoveries. Historians and scientists are interested in the history of science for good reason.According to our current definition of science, the ancient Greeks had no science. Whatever science they had was run by philosophers and doctors.After the Middle Ages there was a constant tendency to free science from philosophy and the general zeitgeist.During the Renaissance and the eighteenth century, scientific beliefs were strongly influenced by scientists' attitudes toward religion and philosophy.The Cartesian school, orthodox Christians or deists (Deist) will inevitably have different ideas on cosmology, generation theory, and various explanations about life, matter, and origin.Nothing marked the emancipation of science from religion and philosophy more definitively than the Darwinian revolution.Since then it has been no longer possible to tell from the author's scientific works whether he was a devout Christian or an atheist.This is true even of what biologists, with the exception of a very small number of fundamentalists, have written about evolution. This current of scientific emancipation has had considerable influence on the writing of the history of science.Looking back, the earlier the time, the smaller the stock of scientific knowledge at that time, and the less obvious the impact.The influence of the general intellectual atmosphere is all the more important.As far as biology is concerned, it was not until about 1740 that scientific questions began to separate from general intellectual debate.So there is no doubt that historians are best suited to discuss issues of earlier periods in the history of biology; whereas the history of the specialized discipline of biology in the nineteenth and twentieth centuries was entirely in the hands of scientists and was not professionalized until recently.This situation is well illustrated by recent publications in the history of science in specialized fields of biology; for example, the history of genetics by Dunn, Stubbe, Sturtevant et al., the history of biochemistry by Fruton, Edsall, Leicester, et al., by Needham and Oppenheimer History of embryology, history of cytology by Baker and Hughes, history of ornithology by Stresemann, etc.Although these are only a few examples from the vast literature, they are enough to show that scientists are competent in the study of history. Most ordinary "science" histories are written by historians of physics who have not fully overcome the narrow view that science is not science unless it fits physics.Physical scientists tend to measure biologists on a scale of value that is the extent to which each employs "laws," measurements, experiments, and other forms of scientific investigation.These forms are highly regarded in the physical sciences.The result is that certain historians of physics have made evaluations of the biological world in the relevant literature so comical that it can only be laughed at.Darwin, for example, is known to have formed his theory of evolution primarily from field observations as a naturalist, yet a famous historian of Newton went so far as to write that "the naturalist is indeed a trained observer." , but his observations differ from those of a gamekeeper only in degree, not in quality. His only knack is familiarity with systematic nomenclature" assertions.It's amazing.This kind of biased physicist is totally unsuited to the study of evolutionary biology, as will be discussed in Chapter 2.The study of theory formation and its history in evolutionary and systems biology requires a fundamentally different approach more akin to that taken by archaeological historians or modern world history commentators. Quite naturally, not only physicists but every specialist considers his own field of study to be the most interesting and the method of study to be the most effective.As a result, there is often a repulsive chauvinism between fields of study, and even within a field of study (such as biology).For example, in Hartmann's (1947) pseudonym "General Biology", 98% of the space is devoted to physiological biology, while only 2% is allocated to evolutionary biology.Another example is that some historians attribute the establishment of evolutionary synthesis entirely to the discovery of genetics, ignoring the contributions of systematics, paleontology, and other branches of evolutionary biology (Mayr and Provine 1980). Chauvinism is at work. There is sometimes national chauvinism within a research field, which exaggerates or even untruely promotes the importance of scientists in one country, and belittles or ignores scientists in other countries.This is not necessarily due to the abuse of patriotism, but is often the result of not knowing the language of other countries; and some scientists have published important works in their own language.In my own work, I have a deep feeling that due to my ignorance of Slavic and Japanese languages, there is a great possibility of prejudice. The greatest difficulty encountered in the endeavor to identify an enormous number of biological problems and to reconstruct the development of their conceptual structure is the vast amount of data required to be studied.In principle, this includes the entire reserve of biological knowledge, including books and publications published by biologists, their letters and biographies, the situation of their units, social history at that time, and others.Even the most conscientious historian can touch only a thousandth of this material.This situation is exacerbated by the current exponential growth in the rate at which scientific material is published.More articles (and number of pages) were published in a very short few years than in the entire previous history of science.Even scientists complain that they can no longer keep up with the avalanche of research reports in their specialized fields.Curiously, the same is true of historical writing.There are roughly five times as many historians of biology in the United States today as there were twenty-five years ago. Although I have made a bold effort to read many of the most important publications, I know that every expert will find in my book a great many omissions, and perhaps quite a few errors.The first drafts of most of the original manuscripts of this book were written during the period 1970-1976, and publications later than this have tried to include as much as possible, but have not always been able to do so.It should also be mentioned that it would be absolutely impossible to accomplish my task without a rich and excellent sceondary literature.The older literature was often superficial, with authors one after another plagiarizing the same myth or fallacy that could only be discovered when consulting the original sources.There are more than 20,000 independent entries in this book, and it is obviously impossible to check the original documents one by one.Since my book is not a dictionary or a history, occasional errors of fact are harmless.My main purpose is to synthesize a large body of literature and then to focus coherently on the analysis and explanation of causes. A frequent and not unreasonable criticism of historians of science is that they place too much emphasis on the "prehistory" of science, that is to say, only on events in historical periods that have little relevance to modern science.In order to avoid this kind of censure, for non-specialists, I try to bring the issues I want to talk about as close as possible to modern times.In some cases, such as the discovery of multiple types of DNA in the field of molecular biology in the past 5-10 years, the conceptual consequences (eg for evolution) are so unclear that it is too early to say. I disagree with the view of a modern historian who once said: "The purpose of the history of science is to study and discuss those states of affairs that have ended, not the current real problems." This view is very wrong.Most scientific debates are much older in time than is generally believed, and even present-day controversies are often rooted in a very long time ago.It is precisely the historical study of these controversies that has often done a great deal to clarify the concepts and thereby make possible the ultimate resolution of the problems.In the field of world history, "modern history" is considered to be a legitimate territory for picking off heirs. Similarly, the history of science also has its own "modern history."Nothing is more misleading than seeing history as merely dealing with dead problems.Conversely, one might regard prehistory as a statement of problems that were settled centuries and millennia ago. 历史学家在写作时，当论及的问题牵涉面很广（有如本书），就势必只能作高度简化的论述。必须提醒读者，有许多事态发展看起来很简单而实际则很曲折复杂，这种表面上的简单具有很大的欺骗性。如果想要对充斥在某一特定时期的许多对立思潮，虚假的优先地位、无结果的假说等等有一全面认识，就必须参考那些对某一特定的事态发展或较短时期的情况作详尽讨论的专著。事态发展实际上从来不像在简化了的回顾式陈述中那样有条不紊和富于逻辑。当面临新的发现或新概念时，如何有分寸地恰当强调业已根深蒂固的概念化的麻痹作用就特别困难。 给某些科学家贴上各式各样的标笺（如活力论者，先成论者，目的论者，突变论者或新达尔文主义者等等）也能产生差错，好像这些标签所指的会是均一类型。实际上这种分类所包含的个人中从没有两个人具有完全相同的观念。像拉马克主义者和新拉马克主义者这样的称呼就尤其如此，他们除了都承认获得性可以遗传这一点以外，彼此就再也没有丝毫共同之处。 历史学家所遇到的另一个困难是绝大多数科学家都不清楚他们自己的思想体系。他们很少能说明白（如果他们确曾想过）自己坚定地接受哪些真理或概念，彻底反对的又是哪一些。在很多情况下，历史学家只能通过重新组建那个时期的全部理念背景的办法才能将这思想体系串通起来。然而为了回答以前令人困扰的问题，对这些默认的了解就可能是必要的。在科学领域中，人们常常论及优先权和价值体系。这两者对下列情况具有决定作用：当前面的一段研究工作已经完成后，它们决定新研究的方向；研究人员最关心证实或否定哪些学说由它们决定；它们还决定研究者是否认为研究范围已经枯竭。但是迄今为止对决定这一类优先权或价值体系的因素的研究却极不被重视。历史学家必须尽力发现当科学家对一系列熟知事实作出新解释时他是怎样想的。科学史中真正的关键事件总是发生在科学家的头脑中这一说法可能是合理的。可以这样说，当试图去分析研究一位科学家时，必须努力像科学家在进行工作时想的那样去想。 许多科学家倾向于在他攸物著作中只注意新的事实（更确切地说是新发现），特别是那些凡是能引起轰动的事态。与此同时他们一般却又不去记述概念或着重点的随时变化。他们甚至还觉察不到这种变化，即使意识到也认为无关紧要。当一位现代的历史学家企图重现过去几个世纪的这类变化时，他只得把目前的兴趣爱好和价值尺度投射进历史。这样做的危险只有当历史学家充分意识到自己工作的意义时才能降低到最低限度。 我自己是由于读了那夫乔（A．O．Lovejoy）写的《自然界的伟大链索》（The Great Chain of Being）一书才对科学史发生兴趣。他在书中试图——事实上是很出色地完成了——追踪从古代直到18世纪末的某种思想（或某些思想的凝聚复合体）的生命史（可以这样借喻）。我从这一本书学到的东西比我所读过的几乎所有其它的书都要多。另外， Ernst Cassirer和Alexander Koyre也采用了同样的方法。他们为科学史料编纂共同提出了全新的标准。 就科学史来说，聚焦点是问题而不是思想，然而科学史家的治学方法和像那夫乔这样的思想史家的方法并没有太大的不同。和那夫乔相仿，科学史家努力于追溯问题的起源，并从开端起跟踪其演变、分化，直到问题解决，或者是延续至今。 本书的主要目的是在生物学的各个部门、各个时期中去发现：未解决的问题是什么，提出了哪些设想去解决它们；占支配地位概念的实质，它们的演变，这些概念被修正以及新概念产生的原因是什么；最后，当时流行的概念或新产生的概念对延滞或加速当时未决问题的解决有哪些影响。这种处理方式在最理想的情况下将能刻划出生物学中每个问题的全部生命史。 专心致志于这类科学的概念史有时被人贬低为退休科学家的廦好。这种看法忽视了这门学问所作出的多种贡献。正如经常提到的那样，科学史作为科学导论的启蒙最合适。它有助于填补“普遍信念”与科学的实际结论之间的鸿沟，因为它指出了科学为什么和以什么方式超越了世俗信念而向前发展。可以拿生物学的一个分支学科作为例子来说明这一点，在遗传学史中就可以表明是通过什么发展和论据才使一度被广泛持有的错误信念被否定。例如获得性遗传；亲本遗传物质“融合”；雌性只要受精一次其“血液”即被沾污便再也不能产生“纯种”后代；一个卵子同时被几个雄性的精子授精；怀孕的母体遭到意外可引起可以遗传的性状等等。来自民间传说，神话，宗教文书，或早期哲学的类似错误思想本来就存在于生物学的各个领域中。历史地阐明这些前科学的或早期科学的信条逐渐被有充分根据的科学学说和科学概念取代，对阐明现代生物学学说体系是很有利的。 门外汉常常以科学太技术化、太数学化作藉口来为自己对科学无知辩护。我要告诉本书的未来读者，这书中几乎没有数学，专业技术性程度也不致使门外汉难于理解。生物学思想史的主要长处是，缺乏对动植物种的名称或分类学基础知识的人也能学习。但是学习思想史的人必须对生物学的一些基本概念有一定的了解，例如遗传、程序、种群、变异、突现、有机体等等。本书第二章的目的就是介绍一些主要的生物学概念。这些概念（连同有关的术语）有许多已渗入人文科学的某些学科，学习掌握它们只是个教育问题。所有这些概念是了解人（类）及其所处的世界所必不可少的。为了解释人类的起源和人类本性所作的任何努力都必须以透彻了解生物学概念和学说为基础。最后，熟悉少量的专业术语。如配子、合子、种、基因、染色体等等也是有好处的（这些术语可查阅任何生物学辞典）。这些术语的全部生词量远远少于任一人文学科（不论是音乐、艺术或现代史）的学生在自己的专业中所必须学习的。 不仅仅单是门外汉的视野将会由于学习生物学思想史而大大拓展。近来生物学的很多学科的进展是如此迅速，专家们在其本专业以外也难于跟上这种发展。这本书对生物学及其主要概念的广泛综合评述将有助于填补某些空白。我的这些评述还是针对近年来从外界，即从化学、物理、数学或其它邻近领域进入生物学领域的人。这些“新生物学家”的专业技术熟练性很少能被相应的概念熟练性匹配起来，令人不无遗憾。的确，对自然界的有机体以及进化途径都有所了解的人却往往对分子生物学的一些文章所作的某些概括的质朴简洁感到惊讶。不可否认，没有捷径可以补偿这种缺欠。我和Conant一样，认为学习一门学科的历史是理解其概念的最佳途径。只有仔细研究这些概念产生的艰难历怪——即研究清楚早期的、必须逐个加以否定的一切错误假定，也就是说弄清楚过去的一切失误——才能有希望真正彻底而又正确的理解这些概念，在科学领域中，人们不仅要从自己的失误中学习，而且也要向别人失误的历史学习。