Chapter 2 Chapter 2 The Status of Biology in Science and Its Conceptual Structure-1

What is science?What place does biology occupy in science?What is the conceptual structure of biology?One must first answer these questions for oneself before attempting to understand the evolution of any particular concept or problem in the history of biology.To all three of these questions some people, especially some philosophers and non-biologists, have given utterly misleading answers.This seriously hinders the understanding of the history of the development of biological thought.My first task in this chapter is to try to answer these basic questions correctly.This will provide a firm basis for studying the historical development of particular concepts.

Since time immemorial people have asked questions about the origin, meaning and purpose of the world.Tentative answers to these questions can be found in the myths that characterize every culture, even the most primitive.Since then it has proceeded in two very different directions.One direction is that people's ideas are fixed in religion, manifested as a set of dogmas usually based on (above) apocalypse.For example, the Western world was completely dominated by a firm belief in the teachings of the Bible at the end of the Middle Ages, and outside the Western world by a general belief in supernatural powers.

Philosophy, followed by science, was another way of dealing with the mysteries of the world, although science was not strictly separate from religion in its early history.Science approaches these mysteries with questioning, suspicion, curiosity, and the search for explanations, and so it does not take the same attitude as religion.Pre-Socratic (Ionian) philosophers who sought "natural" explanations of these mysteries in terms of observable natural forces (such as fire, water, air) opened the way for this different approach ( see Chapter 3).This effort to understand the causes of natural phenomena is the beginning of science.In the centuries following the fall of the Roman Empire, this tradition was virtually forgotten, only to be revived during the Scientific Revolution in the late Middle Ages.The belief that God's truth is revealed not only in the Bible but also in God's creation was also developed.

Galileo's explanation of this view is well known: "I think that when discussing the phenomena of nature, we should not start from the authoritative position of the Bible, but should start from wise and rational experiments and necessary demonstrations. Because both the Bible and the natural world are Likewise from divine will." He went on to say, "God has revealed himself admirably to us in the acts of nature as in the sacred words of the Bible." Deities minimally inspire faith and faith as much as deities who always intervene in the course of events.It was this kind of thinking that led to the birth of science as we understand it today.For Galileo, science and religion were not incompatible, but an integral part of religion.Likewise, some prominent philosophers from the 17th to the 19th centuries—such as Kant—introduced God into their philosophical expositional formats.What is called natural theology, whatever its name, is actually a mixture of science and theology.The conflict between science and theology came later, when science used "natural laws (laws)" to explain more and more natural phenomena and natural processes. Intervention of special laws of nature can be explained.

The fundamental difference between religion and science is that religion generally has a set of dogmas (mostly "revelation" dogmas) for which there is no room for any other alternative or accommodating interpretation.Science, on the other hand, actually encourages alternative explanations and happily substitutes one theory for another.The discovery of an alternative explanation is often the source of exuberance.The soundness of scientific thought (idea) is evaluated only to a lesser extent by criteria outside of science, since it is generally judged entirely by its efficacy in explaining (and sometimes predicting) problems or phenomena.

Oddly enough, scientists have always been a little unclear about what science is all about.In an age of empiricism and induction, the purpose of science is most often described as the gathering of new knowledge.In contrast, when one reads the works of philosophers of science one gets the impression that, for these philosophers, science is methodology.While no one would ever doubt the importance of method, the almost exclusive preoccupation with method by some philosophers of science diverts attention from the more fundamental purpose of science, which is to improve our understanding of the world we live in and of ourselves.

Science has many purposes. Ayala (1968) put it this way: (l) Science attempts to organize knowledge into systematic knowledge, and strives to discover patterns of relationship between phenomena and processes. (2) Science seeks to provide an explanation for the emergence of events. (3) The explanatory hypotheses put forward by science must be testable, that is to say, these hypotheses can be discarded.More generally, science attempts to encompass the enormous variety of phenomena and processes in nature within a small number of explanatory principles. In the eyes of ordinary people, discoveries are the hallmark of science.Discoveries of new facts are generally easy to report, and the news media view science in terms of new discoveries.When Nobel put forward the conditions for the Nobel Prize, he thought of new discoveries, especially new discoveries that are beneficial to mankind.Yet it is a great misconception to think of science as merely gathering facts.In the biological sciences, the vast majority of important advances are made by introducing new concepts or improving existing ones; this may be truer for functional biology than for evolutionary biology schools.Our understanding of the world is advanced more effectively through the improvement of concepts than through the discovery of new facts, although the two are not mutually exclusive.

Let me give an example or two to illustrate. The 1:3 ratio was discovered many times by plant breeders before Mendel, and even Darwin discovered it many times in his plant breeding experiments.Yet all of this is worthless.It wasn't until Mendel introduced the concept of appropriateness and until Weissmann introduced the concept of complement that Mendel's dissociation phenomenon took on greater significance.Similarly, the phenomena now explained by the theory of natural selection were well known long before Darwin, but were not understood until the introduction of the concept that populations contain unique individuals.The concepts of population thinking and geographic variation, together with the concept of isolation, in turn, were prerequisites for the development of the theory of geographic speciation.The recognition of reproductive isolation as a key component in the speciation process was not complete until the concept of isolation mechanisms was clarified.As long as geographic barriers are included in the mechanism of segregation (Dobzhansky, 1937), the true role of the segregation mechanism is not understood.

Almost arbitrarily, both in evolutionary biology and systematics, one can list a number of examples of progress and show that they are largely the result of the introduction of improved concepts rather than of new discoveries.Historians of science have long recognized this, but unfortunately it is poorly understood among non-biologists.Indeed, discovery is an essential part of scientific progress, and some of the current weaknesses in biology are largely the result of a lack of certain fundamental facts.For example, the origin of life, the organizational structure of the central nervous system.But the contribution made by new ideas, or old ones more or less radically changed, is as important, and sometimes more important, than that of new facts and their discoveries.In evolutionary biology, concepts such as evolution, common origins, geographic speciation, mechanisms of isolation, or natural selection have radically turned a previously disjointed field of biology into new theories and data. The emergence of endless research work.Those who insist that the progress of science consists primarily in the progress of scientific concepts are not wrong.

Of course, the use of concepts is not limited to science, since art, history (and other fields of the humanities), philosophy, and any human thought activity have their own concepts.By what criteria, then, other than the use of concepts, are sciences and other human achievements mentioned above to be distinguished?The answer to this question is not as simple as it might seem, as is the oft-quoted question: To what extent is social science science?The following aspects can be tried to illustrate the characteristics of science, that is, the rigor of methodology; the possibility of testing or disproving its conclusions, and the possibility of establishing a non-contradictory theory system (Paradigms).Method, though not the whole of science, is an important aspect of it, especially since methods are not the same in different disciplines of science.

The Greeks always sought (rational) explanations for a large number of phenomena.For example, when the Hippocrates school explored the causes of diseases, they did not search for the source of diseases from the influence of gods, but attributed them to natural causes such as climate and nutrition.Likewise, the Ionian philosophers attempted to give rational explanations of phenomena in the animate and inanimate worlds.Aristotle, the universally recognized founder of scientific methodology, in his "Posterior analytics" (Posterior analytics) excellently talked about how things should be scientifically explained, and its influence continued almost until the 19th century , as Laudan (1977: 13) pointed out quite radically: “Most philosophers of science are still limited by the methodology proposed by Aristotle and his commentators.” Greek philosophers, including Aristotle, mainly Is a rationalist (rationalist, or rationalist).They (Empedocles being a typical example) believed that scientific problems could be solved simply by precise and clear reasoning, including what we now generally call deduction.The undoubted success of these ancient physicians and philosophers in explaining states of affairs led to an overestimation of the purely rational approach, and Descartes reached its zenith in this respect.Although he also did some experimental research (anatomy, for example), much of the philosopher's writings make one read as if he believed that anything could be solved with a focused mind. The ensuing denunciation of Cartesianism by the inductivists and experimentalists makes it very clear that method is considered important in science.This is exactly as true today as it was in the seventeenth century.It is a pity that many philosophers still believed that the mystery of the universe could be solved only through reasoning or philosophizing until the 19th century.When their conclusions conflict with the findings of science, some of them insist that they are right and that science is wrong.It was this attitude that drew Helmholtz's strong displeasure with the philosopher's domineering.Philosophers' reactions to the theory of natural selection, relativity, and quantum mechanics suggest that this attitude has not completely changed. Descartes demanded to present only conclusions and theories that were as unquestionable as mathematical proofs.Despite constant objections, the opinion that a scientist must provide absolute proof of his discoveries and theories remains common until now.This view dominates not only the physical sciences (where proofs of the nature of mathematical proofs are often possible) but also the biological sciences, where inferences are often uncontroversial and thus can be regarded as It is proof, for example, that the blood circulates or that a certain kind of caterpillar is the larval stage of a particular butterfly; the fact that the most exhaustive explorations of all corners of the earth have not found dinosaurs can be considered proof that the dinosaurs are extinct.I pointed out some facts above and showed whether affirmative assertions that conform to the facts can generally be made.But in most cases, and perhaps most of the conclusions drawn by biologists, it is impossible to provide such conclusive evidence (Hume, 1738).How can we "prove" that natural selection is the directional factor governing the evolution of organisms? Physicists also eventually realized that they could not always produce absolute proofs (Lakatos, 1976), and new theories of science no longer required absolute proofs.Scientists are now content to regard as true the state of affairs that appears most probable on the basis of the available evidence, or is consistent with more facts or more convincing facts (rather than consistent with competing theories).Recognizing that it is impossible to provide absolute proofs for many scientific conclusions, the philosopher Karl Popper proposed to use falsifiability to test the correctness of these conclusions.This shifts the responsibility for causing controversy to the side of the opponents of the scientific doctrine.In this way the doctrine which survives the greatest number and every attempt to deny it will be accepted.Popper's suggestion also draws the line between science and non-science very cleanly: any claim that cannot be disproved in theory is not science.Therefore, the claim of human existence in Andromeda is not a scientific hypothesis. Sometimes, however, it is as difficult to provide counter-evidence as it is to provide positive evidence.Therefore, counter-evidence cannot be considered the only means of obtaining scientific acceptability.As reflected in the history of science, some scientific theories are often rejected not because they have been completely refuted; but because new theories seem more likely, simpler, or higher in style.In addition, some theories that have been denied are often held tightly by a small group of believers regardless of the strong criticism of others. The new doctrine of science, based on the probabilistic interpretation of scientific conclusions, makes it untenable to regard truth or proof as something absolute.This is for biology.Some sectors are more important than others.Every evolutionary scholar is often asked when talking to the layman: "Is the theory of evolution proven?" nature. The actual working scientist is different, he is always practical.He is always content with a theory until he comes up with a new and better one.Factors that are difficult to explain are treated as black boxes (黑睡) in the same way that Darwin treated sources of genetic variability (an important component of his theory of natural selection).A scientist was or is never unduly troubled by the fact that many of his generalizations are merely probabilistic and that many natural processes have a highly random component.Acknowledging that scientific theories are highly flexible, scientists are willing to test various theories, combine elements of different theories, and sometimes even consider several alternative theories at the same time (multiple working hypotheses). He has a choice in seeking evidence (Chamberlin, 1890).It should not be hidden, however, that the open-mindedness of scientists is not without limits.When scientific doctrines are "new" or entirely different from the prevailing intellectual background, they are ignored or suppressed.As we shall see later, this does exist, for example with the Concept of emergentism and the level specific pronerties of hierarchies. It is worth noting that Darwin's views are completely consistent with modern teaching.He realized that he could never explain the results of evolution with the certainty of a mathematical proof.He is in On the Origin of Species.It is mentioned in about two dozen different places in ; "Is this particular finding—either distributional pattern or anatomical structure—easier to explain by creationism or by evolutionary opportunism?".He has always insisted that the latter is more likely.Darwin already anticipated many important principles of modern philosophy of science.Although scientists now generally adopt probabilistic (theoretical) explanations of scientific truth—in fact, it is completely impossible to provide mathematically proven deterministic explanations for most scientific conclusions—this new insight has still not been accepted by many very Appreciated by scientists.It pays to include this new conception of scientific truth as part of a wider science education. There are signs, however, that the importance of methodological choice has been overstated.On this I agree with Koyre (1965) that "abstract methodology occupies a rather small place in the concrete practical development of scientific thought." Goodfield (1974) Reductionist and anti-reductionist among physiologists No difference was found between them in their scientific achievements and theories they founded.Kuhn and others also downplay the importance of method choice.Scientists often go back and forth between different stages in actual research work. In one stage, they collect data or conduct pure descriptive or classification research, and in another stage, they establish concepts or test various theories. The debate over the merits of inductive and deductive methods has been going on for centuries.It is now clear that this is a relatively irrelevant debate.Inductivism claims that a scientist can draw objective and unbiased conclusions simply by recording, measuring, and describing what he encounters without any prior hypotheses or prior expectations. F．Bacon (1561-1626) was the main founder of induction theory, although he never used this method consistently in his own research work.Darwin, who boasted of inheriting the "true Baconian method," was not an inductionist.He did mock the method, saying that if anyone really believed in it, "he'd better go to the gravel-yard, and count the boulders there, and describe their color."But in some philosophical literature, Darwin is often classified as an inductionist.Inductive theory was all the rage in the eighteenth and early nineteenth centuries, and now it is recognized that a purely inductive treatment is completely useless.This situation is illustrated by the example of the plant breeder Gaertner, who patiently conducted and recorded thousands of hybridization experiments without finding any general conclusions.Liebig (1863) was the first famous scientist to come out against Bacon's inductive theory, arguing convincingly that no scientist had ever been or could follow the method set forth in (Novum Organum).Liebig's scathing critique ended the reign of induction. Inductive theory is being replaced more and more consciously by the so-called hypothetical-deductive method.The first step in this method is to "speculate" (Darwinian), that is, to develop a hypothesis.The second step is to conduct experiments or accumulate observations in order to test hypotheses. Ghiselin (1969), Hull (1973a), Ruse (1975b) have made very good illustrations of Darwin's use of this method.This approach has a strong air of common sense, and one could argue that it was already implicit in Aristotle's method, and indeed a large part of Cartesian deductivism did.Although the deductive method was overshadowed for a time when inductive theory flourished in the eighteenth century, it became the dominant method in the nineteenth century. The hypothesis-deductive method is widely used because it has two advantages.First, it was very much in tune with the growing beliefs of the time.The belief is that there is no absolute truth and that all conclusions and theories are constantly tested.Second, associated with the new relativism, it encourages the constant establishment of new theories and the search for new experiments and observations to confirm or refute new hypotheses.It has made science more flexible and aggressive, and it has made some scientific debates less intense because they are no longer about winning or losing the struggle for ultimate truth. The extent to which scientists actually use the hypothesis-deductive approach is debatable. Collingwood (1939) put it very well. He believed that a hypothesis is always a tentative answer to a question, and asking a question is really the first step towards establishing a theory.The history of science is littered with instances where a researcher had all the important facts necessary to develop a new theory, but just couldn't ask the right questions.If the importance of asking the question is admitted, new questions immediately follow: first, why the question is asked, the answer must be that a scientist has observed something that he does not understand, or that the cause of these things is not clear, or It was because he encountered some seemingly contradictory phenomena and he wanted to eliminate the contradictions.In other words, the observation of things begs the question. Of course, opponents of the deductive method would argue that these things in themselves can never form a theory, and they are quite right.These things only make sense when an inquisitive person asks an important question.Schopenhauer once said that people with creative thinking will "think of what no one has ever thought of, and see what everyone has seen".Therefore, in the final analysis, imagination is the most important prerequisite for scientific progress. Hypothesis-deduction method is, in essence, a modern scientific method for discovering new things, although observations and questions must be raised before tentative hypotheses can be established. The distinction between research in physics and research in biology is not due to methodological differences, as is commonly thought.As a research method, experimentation is not limited to the physical sciences, but is a major method in biology, especially in functional biology (see below).Observation and classification are obviously more important in the biological sciences than in the physical sciences, yet they are also clearly the main methods in some physical sciences like geology, meteorology, and astronomy.Analysis is equally important in physical science and biological science, which will be discussed below. Philosophy of science written by physicists tends to view experimentation as the unique method of science.This is not true, because in some sciences such as evolutionary biology and oceanography, other rigorous scientific methods are very important.Each science requires its own proper methods.For Galileo (mechanics), mechanics, measurement and metrology were very important; for Aristotle (biology), analysis of biological organisms, diversity, purposive processes, and classification were the methods of emphasis.In physiology and other functional biology, experimental methods are not only appropriate but almost the only way to achieve results. The vast majority of historians of the physical sciences have often displayed profound ignorance when discussing methods other than experimental ones.Morgan (1926) faithfully portrayed the arrogance of the experimental scientist in his writings.He completely denies a fossilist's ability to formulate theories: "My friend the fossilist (by whom he no doubt refers to H. F. Osborn) is in a much worse position when he abandons the work of description and tries to turn to the explanation of phenomena." What he knows is more dangerous. He has no way of testing his assumptions... [When seeing the gap in the fossil record] I said to the fossilist: because you don't know, and in your case never It is possible to know whether the difference was caused by one change (a single mutation) or a thousand changes, so you cannot tell us anything with certainty about the genetic unit of the evolutionary process." It seems that no valuable inference can be made from the data, and the inference can be verified by various methods.The notion that experimental work is anything but descriptive can also be misleading.When the operator of an experimental method reports the results of his experiments, it is as descriptive as when the naturalist reports his observations.Complementing experimentation is observation.Progress in many sectors of science depends on observations—observations made in order to answer well-posed questions.Modern evolutionary biology, behavioral biology, and ecological biology have all confirmed that these actual sciences are nothing but descriptive (narrative) sciences.In fact, many articles with basic experiments that don't ask the right questions (there are too many of them :) are more descriptive than most non-experimental works in evolutionary biology. Mere observation is not enough, however.It was not until the late eighteenth century that a method particularly suited to the study of diversity was first seriously employed, the comparative method.Although there were some predecessors before Cuvier, he is undoubtedly the great founder of comparative law (see Chapter 4).People often overlook the need to classify the items to be compared before using the comparative method.Indeed, the success of comparative analysis is largely determined by the perfection of ex ante classifications.At the same time, differences revealed when comparisons are made often lead to improved classification of phenomena.Such back-and-forth (rather than circular) movement between the two approaches is characteristic of many disciplines (Hull, 1967). The difference between experimental and comparative methods is not as great as it may appear at first glance.Both methods involve the collection of data, and observation plays a key role in both (although the experimental scientist usually does not refer to the results he obtains as a result of experiments conducted by observations).In so-called observational science, observers study experiments in nature.The main difference between these two types of observations is that in contrived experiments the conditions can be chosen so as to examine what factors determine the outcome of the experiment.In a natural experiment, whether an earthquake or the appearance of an island animal, our chief task is to deduce or reconstruct the conditions from which the natural experiment proceeded.The reliability of a controlled experiment can sometimes be found almost in "controlled" observations by seeking a set of factors that fit together correctly.As Pantin (1968: 17) once pointed out, "In astronomy, geology, and biology, the observation of natural events at selected times and places can sometimes provide information quite sufficient to draw conclusions, just as information can be derived from experiments. " It is important to emphasize the scientific legitimacy of the observation-comparison method, since the experimental method is not applicable to many scientific problems.But, contrary to what some physicists believe, those branches of science that rely on comparative methods are by no means inferior.As a wise scientist, E. B．Wilson, said long ago: "The experiments done in our laboratories complement those that have taken place and continue to take place in nature, and their results must be woven into the same fabric." E.B. Wilson ) has consistently opposed the view that progress in biology "can only be made by experiment," and that the discovery of heterogeneous plants and animals through observation forms the basis of biogeography; observations revealing the diversity of the organic world, leading to the Linnaean hierarchy The establishment of structures and the theory of common origin; observations led to the birth of ethology and ecology.In biology there may be more insights generated from observation than from all experiments combined. When confronted with myth or religion, science forms a united front.The common purpose of all sciences (although the various disciplines are different) is to try to understand the world.Science calls for explanations, for generalizations, for the determination of the causes of things and processes.At least in these.Aspects of science are consistent (Cansey, 1977). From this situation it often follows that what is true for one science (such as physics) must be equally true for all sciences.For example, I happen to have half a dozen books on the philosophy of science on my shelf that are really just philosophy of the physical sciences.The vast majority of philosophers of science have a knowledge background in physics, and when discussing the philosophy and methodology of science, they are almost entirely based on physical science.These expositions are very incomplete, because they do not include the rich and varied phenomena and processes in the biological world.When philosophers and humanists describe or comment on "science," they almost never have only physical science (and thus technology) in mind.When historians speak of a scientific revolution (which was primarily a revolution in the mechanical sciences), they often imply that the same applies to the biological sciences. There are important differences between biology and the physical sciences, which are often completely overlooked.Most physicists seem to take physics for granted as the model science, and that knowing physics is enough to understand other sciences, including biology."The arrogance of the physicist" (Hull, 1973) has become a proverb among scientists.For example, physicist Ernest Rutherford called biology "postage stamp collecting."Even V., who has never been as arrogant as a physicist, WeisskoPf also recently carried himself away claiming that "the scientific world view is based on the great discoveries of the nineteenth century concerning the properties of electricity and heat and the existence of atoms and molecules" (1977: 405), it seems that Darwin, Bernard, Mendel and Freud (not counting hundreds of other biologists) did not make a huge contribution to our scientific worldview.Seriously, they may have contributed more than physicists. To counteract this attitude, it is sometimes beneficial and even necessary to emphasize the pluralism of science.Newton and the laws of nature have often been viewed from a very early age as being equally extended in time and space as science.However, a look at the intellectual environment of the sixteenth, seventeenth, and eighteenth centuries reveals that several other cultural traditions co-existed at the time, largely independent of each other or of mechanics.The botany of the herbalist, the anatomy of Vesalius, the unique collection box of the naturalist, scientific voyages, botanical exhibitions and traveling animal exhibitions, etc., what does all this have to do with Newton!Yet it was these sciences that inspired Rousseau's romanticism and the creeds that shaped the noble savage. Only in recent years has it been realized how naive and misleading it is to equate the physical sciences with the biological sciences.physicist c. F． von Weizsaecker (1971) admits that the traditional interpretation of physics and "its abstract mathematical formal garb do not meet our needs for a true understanding of nature. And a unified world view can no longer unite the various sciences...Physics Scientists have discovered a biology that is autonomous." The study of biological phenomena thus raises a legitimate question: To what extent are the methodological and conceptual structures of the physical sciences exemplified by the biological sciences?This problem is not only related to some special problems such as "perception" or "will", but also involves any biological phenomenon or concept, such as population, species, adaptation, digestion, selection, competition and so on.Don't these biological phenomena or concepts have counterparts in physical science? Nowhere is the difference between the different sciences more apparent than the difference between their philosophical applications.Many philosophers have pointed out that there is no conceivable connection between the physical sciences and ethics.Equally evident, however, is a seemingly possible connection between biological science and ethics: e.g., Social Spencerism, eugenics, etc. Physicists claim that there is It is true that there is no connection (think of nuclear physics). But if he formally states (as many physicists do) that there is no connection between "science" and ethics, he is revealing the narrowness of the department. Politics Ideology has always been more interested in the biological sciences than in the physical sciences. Lysenkoism and the tabula rasa teachings of behaviorism are but two examples. For the reasons given above, when speaking of the philosophy of science we really mean It is the philosophy of physical science that is wrong. The opinion of many physicists that all knowledge of biology can be reduced to the laws of physics has led many biologists to raise the question of biological autonomy in self-defense.Although this emancipatory movement of biologists has naturally met with considerable resistance; resistance not only from physicists but also from essentialist philosophers, which has gained momentum in recent decades.It is also very difficult to discuss calmly whether the principles and theories of physical science can explain everything in biological science, and whether biology is (at least partially) an independent science.This is due to competition and even hostility among sciences.And this happens both within and between the physical and biological sciences, with quite a few (like Comte) attempting to classify the sciences into hierarchies and canonize mathematics (especially geometry) as the queen of science.This competition is even more pronounced in competition for honors (plus Nobel Prizes), for budgets in universities and in government departments, for office, and for social prestige among the general public. The foregoing discussion may give the impression that I am also calling for the full autonomy of the biological sciences, in other words, that I am abandoning the notion of a unified science altogether and replacing it with two separate sciences, physical science and biological science.But this is not my point of view.What I wish to show is that physical science is inadequate as a measure of science.物理学完全不能担任这一角色，因为正如物理学家Eugene Wigner说得好：“目前物理学研究的是极限状态（limiting case）。”用一个类似的比喻，物理学相当于欧氏几何，后者是所有几何（包括非欧氏几何）的极限状态。关于这种情况G· G·辛普森（ 1964b：106～107）阐述得最清楚：“坚持研究有机体需要除物理科学以外的原理并不是对自然的二元论或活力论观点。生命…因此便不会必然被认为是非物理的或非物质的。正是生物受到了千百万年历史过程的影响。……这些过程的结果是和任何非生命系统在种类上不相同的系统，而且几乎是不可比拟的更加复杂。生物并不是由于这个原因在本质上便必然较少物质性或较少物理性。问题的关键是，一切已知的物质过程和解释原则对生物有机体都是适用的，而只有有限的物质过程和解释原则适用于非生命系统…因此生物学是站在一切科学的中心的科学……正是在这个地方、在一切科学的所有原则都被包罗进去的领域之中，科学才能真正的统一起来。” 在生物科学中我们所研究的现象是无生命物体所没有的，这种认识并不是新的。科学史，自亚里斯多德开始，就是力求表述生物学自主的历史，是试图抵制机械-定量式解释的历史。然而每当博物学家和其它生物学家以及某些哲学家强调性质、特殊以及历史在生物学中的重要性时，他们的这种努力往往遭到讥讽并简单地被视为“劣等科学”加以排斥。甚至康德也逃不脱这种命运，他在所写的《判断力批判》（ Kritik der Urteilskraft，1790）中十分令人信服地争辩说生物学和物理科学不同，生物有机体与无生物不同。遗憾的是这些努力被贴上了活力论的标签因而被排斥在科学之外。严肃地对待生物学自主的要求还只是上一代左右的事，也就是说在各种形式的活力论消亡了之后。 只有首先将各种不同的科学彼此加以比较并明确了它们有哪一些共同点，有哪些区别之后才能对科学作出普遍公认的论述，这种看法正在越来越清楚地被人们所认识。下面我们就来讨论生物学有些什么特殊的地方。 “生物学”这个词是在19世纪才有的。在此之前并没有这样一门科学。在培根、笛卡尔、莱布尼茨及康德的有关科学及其方法论的著述中，就只有医学（包括解剖学及生理学）、博物学和植物学（还包括其他内容），而没有提到生物学。解剖学（人体解剖）在18世纪就是医学的一个分支，植物学同样也主要是由一些对药用植物感兴趣的医生在实践中加以研究和运用的。动物的自然史当时主要作为自然神学的一部分而研究，用以对付设计论（design）提出的争议。物理科学的科学革命根本未触及生物科学。直到十九、二十世纪生物学思想才得到革新。因此，在十七、十八世纪建立的而又完全以物理科学为基础的科学哲学没有将生物学包括在内就毫不奇怪（而且在随后修订科学哲学时要再把生物科学包括进去又非常困难）。只是在近二三十年才有一些哲学家（如Scriven，Beckner，Hull，Campbell等）试图将生物学和物理科学之间的区别明确起来（Ayala 1968）。这种思想还很新频，只能作试探性的论述。以下讨论的目的只是阐述有关问题的性质，并不是作出明确的解答。 定律在物理科学中具有重要的解释作用。一件特定的事态只有当它能被证明是由符合于一般定律的特定原因引起的时候才被认为得到了解释。有些哲学家把定律的建立作为评价科学的依据。这样的一些定律被认为是决定论的，因而可以作出准确的预测。 近年来又提出了这样的问题：定律在生物学中是否像在物理科学中那样重要。有些哲学家，如Smart（1963；1968），就根本不承认在生物学中有普遍适用的定律（而这却是物理学的特征）。另一些哲学家，如Ruse（1973）以及（在一定程度上）Hull（1974）则坚持强调生物学也有自身的定律。生物学家们却几乎毫不重视这种争论，认为这个问题与从事实际工作的生物学家毫无关系。 回顾历史就会发现，19世纪的拉马克、达尔文、梅克尔、阿伽西、科普以及许多和他们同时代的人经常提到（生物学）定律；而在生物学的各个学科的现代教科书中却可能一次也遇不到“定律”这个词。这并不是说生物学中不存在规律性，而只是指这些规律性是如此显而易见或如此平凡不值得一提。这可用壬席（Rensch， 1968：109～114）所列出的一百条进化“定律”这件事作为例子很好地说明。这一百条“定律”所指的都是受自然选择影响的适应倾向；而且其中绝大多数又常有例外（偶然的或经常的）情况，所以只是“定则”（惯例，rules），而不是普遍的定律。它们只是对过去的事态具有解释意义而不是预测性的（除非是统计性或几率性预测）。当我说“一只占据有一定领域的雄鸟赶走侵犯者的机会是98．7％（或其它的任一正确数字）”，我就几乎不可能声称建立了一条定律。当分子生物学家称蛋白质不能将（遗传）信息重新转译入核酸时，他们认为这是事实而不是定律。 生物学中的概括几乎完全是几率性的。有人曾作出这样的妙语：生物学中只有一条普遍定律，那就是一切生物学定律都有例外。”这种几率性的概念化与在科学革命早期认为自然界事物的原因都由可以用数学形式表达的定律支配的看法相去甚远。实际上这种思想显然首先是由毕达哥拉斯提出的，它一直到现在，仍然是主导思想，特别是在物理科学中。它一再成为某些综合性哲学的基础，虽然不同的哲学家对之有很不相同的表述形式，如柏拉图的本质论、伽利略的机械论、笛卡尔的演绎法。这三种哲学对生物学都有重要影响。 柏拉图的思想是几何学家的思想：一个三角形不论它的三个角是怎样组合的，它总是三角形的形式，因而和四边形或其它任何多边形是不同的（不连续式不同）。就相拉图看来，世间各种变化无常的现象不是别的，仅仅是数量有限的固定不变的形式的反映，这固定不变的形式相拉图称之为eide，中世纪托马斯主义者则称之为本质（essences）。本质是真实的，在世间是重要的；而作为思想，则本质可以不依赖实体而存在。本质论者特别着重恒定不变和不连续这两点。变化或变更被认为是作为基础的本质的不完善显示。这一概念化不仅是托马斯主义者的唯实论的基础，而且也是后来所谓的唯心主义或一直到20世纪的实证主义的基础。Whitehead是一个数学家和神秘主义者的奇怪混合型人物（也许应当称之为毕达哥拉斯学派人物），他曾经说过：“对欧洲哲学传统最保硷的一般描述是，它存在于对柏拉图的一连串注脚（footnotes）之中”。毫无疑问，这话如果是真的，则看来是赞扬而实质上却是贬低。这话真正指的是欧洲哲学经过了这么多世纪一直没有能摆脱柏拉图本质论的窠臼。本质论，连同它对恒定不变，不连续以及典型价值（模式概念，typology）的强调，一直支配着西方世界的思想，以致研究思想意识的历史学家到现在对之还没有充分认识。达尔文是首先反对本质论（至少是部分地反对）的思想家之一。他完全不被同时代的哲学家（他们全是本质论者）所理解，因而他的通过自然选择的进化概念就无从被人接受。按照本质论，真正的变更（变化）只能经由新本质的突然发生而实现。因为达尔文所解释的进化必然是渐进的，所以和本质论是完全不能和谐共存的。然而本质论哲学和物理科学家的思想却十分合拍，物理学家的“类别”（classes）是由完全相同的实体组成，不论是钠原子、质子、还是π-介子。 就伽利略看来，几何同样是开启自然定律的钥匙。然而他和柏拉图比较起来却更多地以数学方式来运用它。他曾写道：“在宇宙（它永远让我们注视着）这本大书中写上了哲学。除非首先学会它的语言和构成这语言的文字，否则就无法理解这本书。这书是用数学语言写成的，它的文字是三角形、圆和其它几何图形；没有这些，人类就根本无法理解这本大书中的任何一个单词；没有这些人们就只能在漆黑的迷宫中徘徊”（《计量者》）。然而对伽利略来说，不仅几何而且数学的一切方面，特别是测量的任何计量都被他认为是最基本的。 “世界观机械化”——这种信念认为，世界是由创世主按有限数量的永恒规律（定律）所设计的，因而井然有序，有条不紊（Maier，1938；Dijksterhuis，1961）——在随后的几个世纪中得到很大发展，直到牛顿将天体力学和大地力学融为一体时更取得了极大胜利。这些辉煌成就使得数学赢得了几乎无限的声誉。这具体地表现在康德的有名（或名誉极坏！）格言中：“在自然科学的各个领域中只有在包含有数学的那些领域才能找到真正的科学”如果这话是正确的，那末又怎么能算得上科学著作？毫无疑问，达尔文对数学的评价是很低的。 对数字和数量的魔力的盲目迷信，在19世纪中叶或许已达到顶峰。即使是洞察入微的思想家Merz（1896：3O）也曾说过：“现代科学只规范它的方法而不阐释它的目的。现代科学奠基于数字和计算之上，简而言之，奠基于数学运算上；科学的进展既取决于将数学观念引进到显然不是数学的学科中去；又决定于数学方法和数学概念本身的拓展。” 尽管随后对此有不少强有力、甚至极尽挖苦能事的反驳（Ghiselin，1969：21），而具有数学或物理学背景的哲学家却仍然紧抱着数学是科学皇后的魔杖不放。例如数学家Jacob Bronowski（1960，P．218）就曾讲道：“时至今日，我们对任何科学的信赖程度大致和它运用数学的程度成正比。…我们认为物理学真正是一门科学，然而化学则多少沾染有烹调手册的怪味（和污名）。当我们进一步转向生物学，随后是经济学，最后到社会科学，我们就很快地滑落到偏离科学的泥坑中去。”关于定性科学和历史科学、或涉及到系统如此复杂无从用数学公式表达的科学门类的这样一些误解，最后归结为一句专横武断的宣告：生物学是一门劣等科学。这样就导致了在生物学的不同学科中滥用数学解释的现象。 没有人比笛卡尔对数学的重要性更加感受深刻，然而对他的思想的这种赞扬的结果却和对伽利略或牛顿的赞扬结果十分不同。笛卡尔对数学证明的严密性以及针对某一问题所作结论的必然性具有极其深刻的印象，竟至于声称数学定律是由上帝授旨，正如皇帝在其帝国内颁布法律一样。笛卡尔拟定了一种运用数学方法（严格按演绎法）的逻辑以获取理性知识。这种逻辑采取了数学的思想结构而不是用数学公式或方程式作为语言，然而它赞同严格的决定论解释和本质论思想。采用笛卡尔的数学方法论的莱布尼茨则是数学逻辑的创始人。 虽然数学挟其绝对优势支配科学达数百年之久，但是几乎从一开始就有人持不同意见。Pierre Bayle（1647—1706）似乎是不承认那种把数学知识看作是用科学方法所能取得的唯一知识的看法的第一个人。例如他断言历史的必然性并不比数学的必然性低劣而只是有所不同。历史的事实，如罗马帝国曾经一度存在过这一事实和数学中的任一事实都是一样确实可信的。生物学家同样可以坚持过去曾经有恐龙和三叶虫存在，这和数学定律是同样真实的。Giambattista Vico对笛卡尔以数学-几何解释世界的观点也给予了无情的抨击。他确信、观察、分类、假说的方法不容置疑地可以提供关于物质世界的真正而又质朴的“户外”知识。 博物学是对伽利略关于科学的数学理想的第二个反叛根源。布丰特别致力于促进博物学的发展。他强调指出（《哲学著作集》oeuvr．Phil.,：26）有些学科过于复杂不可能有效地运用数学，在这些学科中就包括博物学的各个部门。观察与比较是切合这些学科的科学方法。布丰的“博物学”（Histoire naturelle）对Herder产生了决定性的影响，后者又影响了浪漫主义派和自然哲学派。甚至康德也在179O年放弃了他对数学的崇拜。如果关于科学的数学理想的无效性在以前还并不明显，那末随着的出版这就肯定无疑了。 顺便应当提到的是，将数学看作是“科学皇后”是多么容易引起误解。数学只是科学的一小部分，正像文法只是语言（如拉丁语或俄语）的一小部分一样；数学是和一切科学有关的一种语言（虽然程度极不一致），或者同什么也无关。有一些科学，如物理科学和大部分功能生物学，其中定量和其它数学处理具有重要的解释作用或启发作用。也有像系统学和大部分进化生物学这类的科学，其中数学的贡献就极其微小。 实际上，在这些门类的生物学中考虑不周地运用数学有时会形成模式概念，从而形成错误观念。例如遗传学家约翰逊就经受不住这种诱惑将遗传上可变的种群“简化”为“纯系”，从而混淆了“种群”的确切涵义，在关于自然选择的重要性上就作出了错误的结论。同样，，数学种群遗传学的创导者为了使数学易于处理，将进人演算公式的各种因子加以过份简化。这样就对基因的绝对适合值（absolute fitness value）加大了胁强（stress），过份估价了累加基因效应（ additive gene effects）并进而作出了自然选择的目标是基因而不是个体的假定。这就必然只能得到不切实际的结果。 当达尔文根据地质学和种系发生现象计算地球年龄至少应当在十亿年以上时，物理学家凯尔文爵士（Lord Kelvin）断然宣称这是错误的，因为他根据与地球同样大小球体的热量散失计算，地球年龄至多只有二千四百万年（Burchfield，1975）。十分引人发笑的是凯尔文怎样能保证，他自己的计算结果是正确的而博物学家达尔文的是错误的。由于生物学是劣等科学，因而错误在何方是不言而喻的。凯尔文根本不承认可能有某种未知的物理因素存在，而这物理因素最终倒可能支持生物学家的计算。在当时的这种知识气氛下有些生物学家走迷了路，用浅近的物理学来解释他们的发现。例如魏斯曼在其早期工作中将遗传性归之于“分子运动”，贝特森则认为遗传性是由于“涡动”（旋涡运动）。这样的一些解释只能阻碍科学进展。 在过去50年中这种情况发生了相当激剧的变化。绝大多数纯属生物学过程的不确定性和物理过程的严格确定性已不再呈现十分明显的差异。在研究银河和星云的涡流效应以及海洋和大气系统的湍流现象中，发现在非生物界中随机过程是多么经常，多么有影响。这一结论并没有被某些物理学家接受。例如爱因斯坦就曾大叫“上帝并不玩骰子!”然而在等级结构的每一个层次都有随机过程出现，小至原子核一直到宇宙起源的大爆炸（big bang）所产生的各种系统。随机过程虽然使得预测是机率性（或不可能）的而不是绝对性的，但随机过程本身和确定性过程一样，是有原因的。只是绝对性预测是不可能的，这是由于等级结构系统的复杂性，每一步有非常多的可能选择，以及同时发生的各种过程之间的无数相互作用。就这方面来说，气象系统与宇宙星云在原则上和生命系统就没有什么不同。在如此高度复杂的系统中可能发生的相互作用的数量是如此之多，根本无从预测哪一个将必然会实际发生。研究自然选择和其它进化过程的学者、量子力学和天体物理学学者在不同的时间而且或多或少是独立地作出了这种相同的结论。 由于上述一切原因，物理学已不再被认为是科学的尺度。特别是涉及到研究人类时，是由生物学提供了方法论和概念。法国总统最近将这一信念用下面的活简洁地归纳了起来：“毫无疑问，被人们考虑不周地称为'精密'科学的数学，物理学以及其它科学…将会继续提供惊人的发现，然而我却不能不感到未来的真正科学革命将必然来自生物学。” 生物学家通常并不建立定律而是将他们的概括组织成概念结构（体系）。有人认为定律与概念的比较只是形式上的差异，因为每个概念都可以转化成为一个或几个定律。即使这种看法表面上是正确的（我对此却并无十分把握），这样的转化在实际的生物学研究工作中却并不见得有什么好处。定律不具备概念的灵活性和启发性。 生物科学的进展大多是这些概念或原则发展的结果。系统学进展的标志是分类、种、类目、分类单位（分类群）等等这样一些概念的提炼和完善；进化生物学的进展则是由于世系、选择以及适合度等概念的发展与完善。生物学的每个部门都可列出一些类似的主要（或核心）概念。 科学的进展在于新概念的开发（如选择、生物种）和用以阐明这些概念的定义的反复提炼与完善。尤其重要的是有时会偶然发现一个多少是专业性术语，过去认为所指的是某一特定概念，而实际上却被用来表示好几个概念，例如“隔离”既表示地理隔离，又表示生殖隔离。又如“变种”，达尔文既将它用于个体，又用于种群，而“目的性的”（teleological）这个术语所表示的却是四种现象。 奇怪的是科学哲学对概念的极端重要性却很不注意，很不重视。由于这个原因，一直到现在还不可能对重要发现的过程和概念发展成熟的过程作详尽的阐述。然而非常明显的是，生物学思想的创导者的主要贡献就在于开发和提炼概念，偶尔还排弃错误的概念。进化生物学的大部分概念都应归功于达尔文，行为学概念则应归功于洛兰茨（Kongrad Lorenz）。 直到现在一直被忽视的概念（历）史中有很多意外情况。“相似”（affinity）、“亲缘关系”（relationship）在进化论以前的系统学中被用来指简单的相似，1859年以后转变成“血缘相近”（Proximity of descent），并没有引起任何混乱或困难。而当亨尼克（Hennig）试图将“单元的”（单源的，monophyletic）这个词从鉴定分类群转变到鉴别世系途径时，在分类学中就产生了很多困难。有时在研究概念时还发现在某些语言中词汇非常贫乏。例如“资源”（resource）这个术语在生态学中非常重要（如资源分配，资源竞争等等）而在德文中却没有相应的词汇，后来才将原来的英文字德语化成“Ressoureen”。 概念的种类很多。例如生物学就认准哲学（quasi－phyilos－ophical）概念或方法论概念的完善化中得益不少；如近期原因与进化原因，比较法与实验法的明确划分。承认比较方法就在生物学中引进了一个新概念。 当引进一个真正的新概念时在科学内部常常引起特别大的困难。例如引进种群思想代替柏拉图的本质论概念，引进选择概念或遗传学中的封闭程序及开放程序等概念时情况都是如此。这正是Kuhn在谈到科学革命时所指的（部分）情形。 有的时候仅仅引进一个新术语，如“隔离机制”、“分类群”（分类单位）、“目的性”，就大大有利于澄清以前概念混乱的情况。更多的情形是必须首先排除概念上的混乱然后再引进新术语这才有利。约翰逊的“遗传型”和“表现型”这两个术语的情况就是这样（虽然约翰逊本人倒多少被它们弄糊涂了；参阅Roll－Hansen，1978a）。 另一个困难是，同一个词在不同的科学中被用来表达不同的概念，或者甚至在同一门科学的不同学科中也有这种情况。例如18世纪的胚胎学家Bonnet或19世纪的动物学家阿伽西使用“进化”这个词其涵义就和达尔文学派大不相同；同样，这个词对人类学家（最低限度对那些直接或间接受斯宾塞影响的）和对选择论者来说涵义又有很大出入。科学史上的很多著名论战几乎完全是由对手双方采用同一个术语而表达的概念十分不同所引起。 在生物学的历史上定义的措辞往往十分困难，而大多数定义又常被反复修订。这种情形并不奇怪，因为定义只是概念的暂时性文字表述，而概念——特别是难懂的概念——常常由于我们知识的增长或理解的深化而需要一再修订。这种情况可以用种、突变、领域、基因、个体、适应与适合度等这样一些概念的定义作为例子充分说明。 科学的一个很重要的方法论方面常常被误解，从而成为对同源现象或分类这样一些概念引起争论的原因。这是定义与在特定场合与定义相符的证据之间的关系（Simnson，1961：68－70）。这最好用一个例子来说明：“同源”（homolosous）这个词在1859年以前就有了，然而一直到达尔文创立了共同祖先学说之后才赋予它以现代流行的意义。按照这一学说，“同源”这个词在生物学上最具有意义的定义是：“在两个或两个以上分类群中出现的某一特征，当这特征来自它们共同祖先的同一（或相应）特征时，这出现于两个或两个分类群的特征就是同源的。”在给定的情况下可以用来证明是否同源的证据应具备什么条件？有一整套这样的标准（例如某一结构相对于其它结构的位置），然而如果将某些学者在为“同源”下定义时所提到的证据也包括进去，那就会引起误解。定义及与定义相符的证据之间的关系同样存在于生物学所使用的几乎一切术语的定义中。例如某人如试图进行“系谱分类”而完全依赖形态学证据去推断彼此之间的关系。就是这样也并不能形成形态分类。目前普遍接受的种的定义包括生殖群落（“品种间杂交”）这一标准。古生物学家不能用化石来验证品种间杂交，但是通常可以把各种不同的其它证据（群聚，相似等等）综合起来以强化同（一）种（类）的可能性。定义阐明概念，但是并不要求包括与定义相符的证据。 下面讨论生物学中一些特别重要的概念。 西方思想自柏拉图以后两千多年来一直受本质论支配。直到19世纪一种新的和不同的关于自然界的思想开始传播，即所谓的种群思想。什么是种群思想？它和本质论有什么不同？种群思想家强调生物界每一事物的独特性。对他们来说重要的是个体而不是模式。他们强调有性繁殖物种中的每个个体和一切其它个体都不相同，即使单亲生殖的个体同样也具有特异性。没有模式的或“典型的”个体，平均值只是抽象概念。过去在生物学中所指的“纲”（ classes）大多数是由独特的个体所组成的不同种群（Ghiselin，1974b；Hull，1976）。 在莱布尼茨关于单胞虫（monads）的学说中就有种群思想的苗头，因为他提出每个单胞虫和其它的每个单胞虫都不相同，这和本质论思想截然相反。然而德国当时是本质论的顽固堡垒，所以莱布尼茨的意见也不可能形成种群思想。种群思想最后在其它地方得到发展，”源流有二；头一个来自英国动物育种学家（Bakewall，Sebright等人），他们发现在他们的畜群中每一个个体具有不同的遗传性状，在这个基础上他们选育了下一代的种畜和母畜。另一个来源是系统学。所有从事实际工作的博物学家都发现在就一个单独的物种收集标本时，虽然收集了“一系列”标本，但从来没有两个标本是完全一样的。这种观察结果使博物学家产生了深刻印象。不仅达尔文在研究甲壳动物时强调了这一点，甚至批评达尔文的人也承认这个事实。例如Wollaston（1860）就曾写道：“在世间的千百万人之中，我们确信无疑地认为从来没有两个人在各方面丝毫不差地完全相似；同样的道理，我们断言曾经存在过的一切生物都是如此（尽管由我们未经训练的眼睛看来它们在某些方面多么相同）也不为过”。19世纪中叶的很多分类学者也发表过类似的议论。这样的独特性不仅表现于个体；而且也表现在任何个体生活史的发育阶段上，并且还表现在个体的群集上，不论群集是属于同类群（demes）、种，还是植物和动物的群聚。考虑到在某个细胞中大量的基因时或开启，时或关闭的情形，身体中从来不会有两个细胞完全相同的论断就完全可能。生物个体的这种独特性就意味着我们在研究生物的集群时，就必须采取完全不同于我们在研究个体完全相似的无机物集群时的方法和态度。这就是种群思想的基本意义。生物个体之间的差异是真实的，而在比较个体的集群（例如物种）时可以计算出的平均值只是人为的结论。物理科学家的种类和生物学家的种群之间的根本差异产生了不同的结果。例如，若不懂得个体的独特性就无法理解自然选择的作用。 本质论者的统计与种群论者的统计截然不同。当我们测定一个物理常数，例如光的速度时，我们知道在相同的情况下它是一个常数，而且观测结果如有任何变化，那就是由于测量不准，统计只表示我们的结果的可靠程度。从Petty和Graunt到Quete－let的早期统计学（Hilts，1973）是本质论统计学，它试图求得真值以便克服因变易而引起的混乱状况。Quetelet是数学家兼天文学家拉普拉斯的信徒，对决定论定律深感兴趣。他希望通过他的方法能够计算出“普通人”（averase man）的特征，也就是说，发现人的“本质”。变易（变化）不是别的，只是围绕平均值的“误差”。 高尔敦（Francis Galton）可能是首先充分认识到易变的生物种群的平均值只是一个抽象观念。在一群人之中身高的差异是真实的，并不是由于测量不准。自然种群统计中最重要的参数是实际变异，它的量和它的性质。变异量因性状和物种的不同而有异。达尔文如果没有采取种群思想就不可能创立自然选择学说。另一方面，充斥在种族主义文献中的言论则几乎完全是基于本质论（类型学）思想。 与引进新概念（如种群思想）同等重要的是排弃或修正错误概念。这可以用目的论这个概念来充分说明。 自从柏拉图、亚里斯多德以及斯多噶学派以后，广泛流行着一种信念（但遭到伊壁鸠鲁学派反对），认为自然界及自然过程都有意向，都有预先决定的目的。十七、十八世纪中具有这种观点的人（目的论者）不仅在自然界阶梯（顶端是人类）中，而且在自然界的统一与和谐以及多种多样的适应中都觉察到某种目的（意向）的鲜明表现。目的论者的对立面是严格的机械论者，后者把宇宙看作是按照自然规律运行的某种机械装置。然而宇宙的表面目的性，个体发育中的有目的的进程，以及生物器官的适应性能等等外观上的目的性是如此明显以至机械论者也不能忽视。一种具有上述全部性