Chapter 17 Chapter 9 Charles Darwin-1

Despite the tireless efforts of many philosophers and some biologists as brilliant as Lamarck, the idea that the world was created by God and was essentially static still firmly dominated the minds of men; until Charles Darwin (or translated as Charles Darwin) (1809-1882) to completely destroy it in one fell swoop.What kind of person is this outstanding scholar?How did his mind get enlightened?What is the reason for his great achievements? Is it because of his education and training, his talent, his diligence, or his talent?These questions have been hotly debated ever since the writings on Darwin have been published in large numbers!

Darwin was born on February 12, 1809 in Shrewsbury, the capital of Shropshire, England.He is the second son of Robert Darwin, a famous local doctor, and the fifth among six siblings. His grandfather was a zoologist, Erasmus Darwin, author of Zoonomia.Darwin's mother, the daughter of the famous potter Josiah Wedgwood, died when Darwin was eight years old. Since then, Darwin has been cared for by his sisters.Our account of Darwin's teenage years and beyond comes almost entirely from his Autobiography (edited by Nora Barlow, 1958), compiled from Darwin's recollections when he was sixty-seven years old as he narrated to his children and grandchildren.Unfortunately, these sources are not entirely reliable; partly due to the decline of his memory in old age, partly because they are written in the overly reserved tone of the Victorian era, so there is no doubt about his own achievements and sufferings. The value and significance of education can only be understated.Some biographers take the material too literally, especially when Darwin disparages his own talents; so these writers are often puzzled afterward: how such a fool could have done such a great thing!What's more, this may well be the greatest rational revolution in history.

Unless we can deeply understand what Darwin himself said: "I am a born naturalist", we will never really know Darwin.All aspects of the natural world sparked Darwin's interest.He enjoyed taxidermy, fishing and hunting, and was an avid reader of nature books such as The Natural History of Selborne by Gilbert White.Like many other young naturalists, the school work was almost a burden to him, and the situation was generally the same at the university.In Darwin's youth, since natural history and other natural science subjects were not legal courses in Britain (this situation continued until the 1850s), when Darwin was only 16 years old (16 years and 8 months), his His father sent him to the University of Edinburgh to study medicine (his brother was also sent to the school to study medicine the year before), and the medical courses made him very troublesome, and the lectures of some other courses (such as the famous geologist Robert Jameson) geology taught) he too was bored.Although he was not interested in most courses at the University (as he was later when he transferred to Cambridge), he nevertheless passed his examinations with flying colors out of a sense of duty.

It has long been repeated that Darwin became a naturalist as a result of his experience on the Beagle.But in fact, it's not.When Darwin embarked on the voyage of the Beagle in 1831, he was already a very good and experienced naturalist.I think that in terms of his familiarity with all kinds of organisms, he completely exceeds the level of a PhD in biology in any discipline today.He has an astonishingly extensive knowledge of not only insects, which are his special interests, but also mammals, birds, amphibians, reptiles, marine invertebrates, fossil mammals, and plants. This prowess can be seen not only in his correspondence prior to his voyage with the Beagle, but also in his correspondence with Henslow a month after he boarded the ship, in which he was very concerned about the information collected. The proficiency with which the names of the families and genus of the herbarium can be said casually is really impressive.Although he did make mistakes in some individual identifications, due to the low level of natural history at that time and the limited library materials on the Beagle, these mistakes can indeed be forgiven.

Where did he get the knowledge necessary for a naturalist?He may have known the importance of keeping a diary and keeping detailed records of his observations and collected specimens at Shrewsbury High School, or later as a professor of zoology at the University of Edinburgh and Grant at the University of Cambridge. Henslow, professor of botany, and Sedgwick, professor of geology.He loved to read natural history documents in college and often had contact with geologists, botanists, entomologists and other naturalists. It is obviously better for his future career than to be familiar with anatomy and other medical related courses (As was the education of T. H. Huxley, who strongly supported him) More important.When Darwin was in Edinburgh, he actively participated in the activities of a local naturalist society (Plinian society); he collected and studied marine life in the intertidal zone under the guidance of Professor Robert Grant; he also often visited the local museum and visited the museum curator; In addition, he learned how to taxidermy birds, etc.; in short, he was very attentive to natural history.

According to the customs at the time, the only suitable future career for a child of a wealthy middle class was to be a doctor or a priest of the church.So when Darwin's family found out that he had no interest in medicine, what were they to do? It was the age of natural theology.At that time, the professors of botany and geology at the two famous universities of Oxford and Cambridge were theologians.Darwin's family naturally decided that he should instead study to be a priest.Darwin later agreed.The condition is that he will be a vicar of a rural parish in the future, and his ideal is likely to be the vicar of Selborne Parish like the aforementioned Gilbert White.

Darwin came to Cambridge in January 1828 and obtained a degree in literature (B.A) in April 1831.He studied classics, mathematics, and theology, which were certainly not to his liking, but he persevered enough to carry on, and he came in tenth overall in his examinations, certainly not a top student.However, this allowed him to have plenty of time to do what he was interested in: riding horses, hunting, collecting specimens, talking with like-minded partners, spending a good night together, and so on.So whenever he recalled the old days in Cambridge, he was always full of interest. "But what a wonderful enjoyment it is to be keen on catching beetles immediately after the pursuit of nothing in Cambridge!" ("Autobiography" 1958: 62).This hobby of Darwin was developed at an early age, and later became his "strange" numbness.Through this kind of friendship Darwin and his cousin W. who was also studying at Cambridge University Christian College at that time Darwin Fox formed a deep friendship.It can be said that FOX led him into the field of entomology, and later insects became a hot topic of frequent communication between Darwin and FOX.

Nothing had the greatest influence on him at Cambridge than the reverend J.S. Henslow, professor of botany, and his friendship.Henswei is not only a devout orthodox Christian, but also a passionate and persistent naturalist.Not only did he receive natural history students at home every Friday night, questioning each other and discussing together, but also "I often walked with him in the late period of Cambridge; so some tutors (dons) in Cambridge gave me a Nickname: 'The Man Who Walked With Henslowe'." From him Darwin learned a great deal about botany, entomology, chemistry, mineralogy, and geology.At the Henslow home, Darwin also met William Whewell, Leonard Jenyns, and some other friends who later corresponded frequently.

Many people fall into two different types of scholars, visual or auditory.In his autobiography, Darwin described some of his experiences in detail, showing that he had the extraordinary visual memory necessary for an excellent naturalist and taxonomist.Since Darwin was clearly a visual type, he benefited little from his professor's lectures. "Compared with reading, the former is not beneficial but harmful." ("Autobiography").Since Darwin was truly educated through observation and reading, it is not unreasonable for him to say later that he was self-taught.Therefore, although it is important to mention some books he read when he was young and which professors he listened to in Edinburgh and Cambridge, the influence of the former is more important.After reading White's Natural History of Selborne, Darwin "observed with interest the habits of birds, and even made detailed notes. In my childish mind I remember asking every gentleman why he was not a bird." Anthropologist" ("Autobiography" p. 45).While at Cambridge he was impressed by the logic and thoroughness of Paley's essays on Christian theology, and he also read Paley's Natural Theology, an excellent introduction to natural history and the study of adaptive phenomena.In Darwin's last year of study at Cambridge, two books greatly influenced him; one was Humboldt's "Per onal Narrative" and the other was Herschel's "Introduction to the Studies of Natural Philosophy" "(Introduction to the study of Natural Philosophy).Darwin regarded it as a treasure, and wrote in "Autobiography": "There is no other book that has had a deeper influence on me than these two books."He learned much about the scientific method from the books of Herschel, who once said, "These two books kindled a burning desire in my heart:

In this hallowed hall of natural science, I want to make even the smallest contribution" ("Autobiography", p. 68). Reading Humboldt's book inspired his ambition to be an explorer, and ideally to South America. Go on an adventure. As luck would have it, Darwin's wonderful vision soon came true. Since Darwin did not enter Cambridge University before Christmas, he had to complete two semesters of courses after his BA degree.Henslow advised him to use the time to specialize in geology.He also arranged for Darwin to follow Geology Professor Sedgwick to conduct a geological survey in Wales, during which Darwin learned to draw geological maps.When he returned home he received an invitation to join the Beagle's next voyage as a naturalist.Although his father objected, Darwin's uncle believed that "studying natural history is certainly not a profession, but it is very suitable for the priest's duties." Finally convinced Darwin's father.

All Darwin biographers agree that Darwin's voyage on the Beagle was the key to his life.Darwin was only 22 years old when the Beagle sailed from Plymouth Harbor on December 27, 1831. When he returned to England on October 2, 1836, he was already a mature and experienced naturalist, almost more mature than he was then. All naturalists are more experienced. Although this voyage provided Darwin with a more rare opportunity than any other, it must be clearly understood that only a person with Darwin's talents and qualities can make full use of this opportunity.This person must possess high enthusiasm, penetrating observation skills, great patience, selfless perseverance, orderly work, and perhaps most of all, an irrepressible curiosity about any natural phenomenon that comes across.All of this has to be paid for.Life on the Beagle was extremely difficult, especially since Darwin was prone to seasickness.For the first three weeks after setting sail, Darwin was so seasick that he could barely move.When he saw the land for the first time during the voyage, he once thought of packing his luggage and going ashore, but he finally gave up this idea and stayed on the ship (the Beagle was originally scheduled to sail for two years, but it was later extended to five years). He gets seasick when the weather turns bad. Although Darwin participated in the voyage as a naturalist, it was he who received and spent most of his training and time in geology.When he boarded the Beagle, he took the first volume of Lyell's "Principles of Geology" just published. In October 1832, he received the second volume in Montevideo, the capital of Uruguay. Lamarck and the content of evolution.These two volumes gave Darwin a thorough understanding of Uniformitarianism, and at the same time raised many questions in Darwin's thought, which were revealed successively in the following years.Darwin made daily observations aboard the Beagle, and placed these observations within a profoundly interpretive framework.In his autobiography he presents himself as a bum with hard-won habits, when in reality he was the hardest-working and hardest-working man on the crew.His cramped cabin forced him to be extremely tidy, and it is not for nothing that Darwin later attributed the method of filing his notes to the strict discipline of the Beagle.Regarding his original intention to become a priest, he said that "when I left Cambridge and set foot on the Beagle as a naturalist, it disappeared naturally" ("Autobiography" p. 57).His letters home and to Henslow on that voyage, as well as the specimens and parts of his diary brought home did cause a sensation for a while, so when the young Darwin returned to England, he was already a little famous, and no one was there anymore. Against his formal choice of naturalist as his profession. After returning to England in October 1836, Darwin first went to Cambridge to sort and arrange the specimens he had collected. On March 7, 1837 he moved to London. In January 1839, he married his cousin Emma Wedgwood. In September 1842, the young couple moved to a small village called Down, 16 kilometers south of London, where they lived all the time. Darwin died (April 1882 19th).After living in the country, he seldom went to London, and rarely traveled except to attend a few academic conferences and recuperate. He never went to Europe after 1827. The move to the country was entirely out of Darwin's health needs, as his health began to deteriorate shortly after he moved to London. Feeling extremely tired.After Darwin was thirty years old, he often couldn't work more than two or three hours a day, and sometimes he couldn't work for several months.His exact etiology has never been ascertained (Colp, 1977), but all symptoms suggested a dysfunction of the autonomic nervous system.Some, if not all, of these symptoms are common among hard-working, hard-working intellectuals.Despite Darwin's frequent illnesses, it is unimaginable that he wrote such a large number of books.Darwin was able to complete these works because he adopted a special way of working, that is, seclusion in the country, avoiding the interference of various conferences, academic duties and teaching burdens.Last but not least, he had a faithful companion who watched over him at all times. Not so long ago, we knew Darwin only through his published works, his somewhat abridged autobiography, and two selected volumes of his correspondence.Since the 100th anniversary of Darwin's publication held in 1959, the real "Darwin industry" (Darwin industry) has developed rapidly.Two or three volumes of new writing on Darwin are published each year, in addition to countless magazine articles.The excavation of Darwin's invaluable wealth of unpublished notes, manuscripts and letters (the vast majority are housed in the Cambridge University Library) is still going on. learn.Also, new material does not entirely help to eliminate differences of opinion in interpretation; in fact, it may raise new questions than it has answered old ones.Due to the limited space of this book, it is impossible to provide a comprehensive and careful analysis of these disputes, and it is impossible to attempt to reach a fair decision.My presentation in this book will necessarily be subjective and eclectic, but I will try to offer my own, logically ordered insights into the major issues in the Darwinian literature.Before discussing the development of Darwin's concept, the concept of evolution must first be clarified.Only by sorting out the inexhaustible threads woven into Darwin's theory of evolution can we understand how Darwin became an evolutionist and recognize the essence of the opinions opposing him. A review of the various definitions and terms proposed for evolution since 1800 clearly shows the vagueness and ambiguity that have always baffled evolutionists, even today (Bowler, 1975) .Can it be said that "evolution is the history of the biological world"?Especially not, because discrete creation (theory) can also be included in this definition; and what is more important, this definition does not indicate that biological evolution includes two basically independent processes, namely evolution (transformation) and diversification ( diversification).The definition generally adopted in recent decades is: "Evolution is the change of gene frequency in a population", which only refers to the evolution part, and does not specify the proliferation of species, and more broadly, does not mention the origin of biological diversity. A broader definition that includes both evolution and diversification is also needed.Evolution involves the "vertical" (generally adaptation) part of change over time; diversification involves simultaneous processes (e.g. multiplication of species), which may be called the "horizontal" part of change, resulting from the and changes shown by incipient Species.Although Darwin was aware of the difference between the two (The Red Notebook, p. 130, Herbert, 1979), it is a pity that he later did not fully emphasize the significant independence of these two parts of evolution, which is what caused Darwin after ( post-Darwinian) for several arguments.Two scholars after Darwin clearly separated these two parts (patterns) of evolution. Gulick (1888) called evolution monotypic evolution and diversification polytypic evolution. Romanes (1897) adopted Gulick's above terminology and regarded evolution as "transformation in time" and diversification as "transformation in space". Both Gulick and Romanes (particularly Romanes) recognized that these were two very different parts of evolution, but this insightful view was largely forgotten after 1897 until Mayer (1941) and others It was restored again when the Synthetic Theory of Evolution was created. Lamarck focuses almost exclusively on evolutionary (vertical) evolution.He emphasized change over time and development from lower to more complete taxa, whereas Darwin was the opposite, more concerned with diversification (horizontal evolution), especially early in his career. Thus, the two founders of evolutionism established two traditions that have survived to the present day (Mayr, 1977b).Most evolutionists focus on only one of these aspects and know little about the other.For example, the famous scholars of the new systematics almost all pay attention to the origin of diversity, while the vast majority of paleontologists until recently only pay attention to vertical evolution, that is to say, only pay attention to phyletic evolution (phyletic evolution), evolutionary progress (evolutionary advance). ), adaptive shift, and the acquisition of evolutionary novelty.Comparative anatomists and most experimental biologists have similar preferences.They do not investigate the nature of species as reproductively isolated populations, nor do they explore the mechanisms of reproductive isolation; that is, they completely ignore the problems of population evolution and species multiplication. When and how Darwin became an evolutionist has been debated.Because the transition from an absolute belief in creation to a firm belief in evolution requires a profound conceptual—in fact, ideological—transformation.First of all, we must consider Darwin's attitude towards Christianity, because it is impossible for fundamentalists to put forward the theory of evolution, so Darwin's change of belief is closely related to our understanding of him turning to evolutionism. Darwin was apparently brought up in orthodoxy; he did not know until much later that his father was an agnostic, or, as Darwin put it, a skeptic.Darwin's favorite book was Milton's (Paradise Lost), which he kept with him when he sailed on the Beagle.He read a lot of theology before he went to Cambridge to study theology. "Because I didn't doubt a word of the Bible at that time, I convinced myself that our (Church of England) creeds must be fully accepted without qualification." Among his favorite readings at that time were the natural theologian Paley's writings. "Because I have no doubts (Paley's premise), I love and believe in the long arguments in the book." While on the Beagle, Darwin wrote: "I am very orthodox, and I remember the ship's Some of the officers (though they themselves were orthodox) have frankly laughed at me for citing the Bible as an irrefutable authority on certain moral matters (Biography, p. 85). His orthodoxy also implicitly included a created world populated by unchanging species.Some of the scientists and philosophers Darwin had most contact with in Cambridge and London, such as Henslow, Sedgwick, Lyell, Whewell, etc. basically held similar views.Before 1859, none of them reiterated the immutability of species more often and positively than Lyell (although Lyell objected to the idea that the earth was recently formed). Darwin's abandonment of the Christian faith occurred within the first two years of his return to England.This was partly due to his more critical approach to the Bible (especially the Old Testament), and partly because he found the argument that the world was designed (by God) to be untenable.For when Darwin discovered a mechanism—natural selection—that accounted for the gradual evolution of adaptation and variety, there was no need to believe in some supernatural (clockmaker) “clockmaker.” Since his wife and many of his close friends were devout theists, Darwin can only express this view very cautiously in his autobiography.But finally he said: "The secret of the beginning of all things is beyond our ability to explain, but personally I would rather be content to be an agnostic" ("Autobiography", p. 94). In Darwin's scientific writings he addressed this subject only once, in the Epilogue of Variations of Animals and Plants Under Domestication, published in 1868.Here he very bluntly stated that we can only make a choice between believing in natural selection or believing in "an omnipotent and omniscient creator who arranges everything and foresees everything". This brings us to the equally insoluble dilemma between free will and divine destiny” (see p. 432 of the book, see also Gruber, 1974). In short, it is certain that when Darwin set out to In delving into his collection of specimens, his faith in Christianity had weakened enough to enable him to abandon the notion that species remained unchanged. It was at this moment that the question of species became the focus of Darwin's attention. Darwin named his great book because he fully realized that the transition from one species to another is the fundamental problem of evolution.The immutable, essentialist species is a fortress that must be bombarded and destroyed; once this stubborn fortress is destroyed, the idea of ​​evolution rushes out like a flood from a breach in a levee. Strangely, the origin of species did not become a scientific question until the 18th century.As long as there is no clear distinction between species and varieties, as long as it is generally believed that the seeds of one plant give rise to another plant, that is, as long as the whole concept of "kinds" of living beings is obscured , speciation would not be a serious problem.It became a scientific problem only after taxonomists, notably Ray and Linnaeus, insisted that diversity in nature is composed of definite, well-defined species.Since the definition of species at the time was formulated in terms of essentialism, species could only arise from sudden events, sudden changes or "mutations" (a term later coined by de Vry).For example, the explanation put forward by Maupedet is: "Can we explain in this way how from only two individuals the various species have been formed? Their first source is probably only the product of accident, in which the basic particles are not like those in the male parent. as in the maternal and parental generations; every degree of error may produce a new species. By repeated deviations it was possible to form the inexhaustible variety of living things we now see" (1756). Darwin was not the first to focus on the origin of diversity, but Darwin's previous solutions were non-evolutionary. According to natural theologians and other theists, all species and higher taxa are created by God, and Lamarck ascribes spontaneous generation.According to Lamarck, each evolutionary line was formed by the individual spontaneous generation of simple organisms, which then evolved into higher organisms.Such an inference means that nothing is solved. What all essentialists from Maupedet to Bateson appreciate is that if species are defined in terms of patterns, then transient speciation by violent mutation is one of two conceivable modes of speciation A sort of. The fact that such transient speciation (via polyploidy) could actually occur was not demonstrated until the 1920s.Another possible mode of speciation in the essentialist conception was proposed by Linnaeus through hybridization (Larson, 1971).Since Linnaeus discovered three or four natural hybrids and named them new species, he has always believed that all species are derived from hybrids.During the period from 1760 to 1770, Linnaeus' views became more and more outlandish, and finally he even thought that God only created the order of plants, and all taxa below the order up to the species are composed of hybrids ( "Mixed") formed. This conclusion of Linnaeus was strongly opposed by his contemporaries.Kerr Luther, a plant hybrid breeder, conducted numerous species hybridization experiments in the 1760s and proved that these hybrids were not stable (see Chapter 14). These results are completely contrary to Linnaeus' requirements.In subsequent generations of hybrids Kerrud also observed a great deal of segregation, the gradual and inevitable decline of the so-called "new species".This is nothing less than a tranquilizer for essentialists, since it would be inconceivable that a new essence could be produced by mixing and merging two pre-existing essences (eidos). Modern man risks forgetting that virtually everyone was an essentialist before Darwin.Each species has its own species-specific nature, making variable evolution impossible.This is the cornerstone of Lyell's thinking.Nature, in his view, consisted of eternal patterns that were created at a particular time.It "has a fixed limit beyond which offspring from a common parent must never deviate from a certain pattern." He also emphasized: "When there are certain causes, and these causes are so active in nature, they must intervene and prevent the transition between species, and in this case to argue that one species changes into another species. The abstract possibility of . . . is utterly useless" (Lyell, II).But none of these reasons mentioned are to be found in Lyell's Principles of Geology.In short, it is absolutely impossible to accept the idea of ​​evolution before eradicating the dogma of fixed species.Lyell, as well as his "catastrophist" counterparts, have shown that it is possible to satisfy or accommodate the fossil record with a conception of Earth's history that is largely non-evolutionary. Recognizing the dominance of essentialist thought helps to solve another mystery.Why in the past 150 years, from Leibniz to Lamarck and Chambers, all attempts to establish a meaningful and content theory of evolution have failed?Such failures are generally attributed to the lack of plausible explanation mechanisms.This statement was partly true, but the fact that most biologists accepted evolution after 1859 while rejecting the explanatory mechanism proposed by Darwin—natural selection—suggests that this is not the whole story.Such biologists became evolutionists not because they mastered a mechanism, but because Darwin's demonstration of the evolutionary potential of species made the theory of common ancestry possible, and it was so successful in answering questions that had been held before. Almost all problems of biological diversity are enigmatic.Eliminating the concept of species invariance and raising and answering the question of species multiplication are the necessary foundations for a correct theory of evolution. Darwin's new way, new way of studying evolutionary problems did not come from Lamarck or other so-called pioneers. They all only care about vertical evolution, how to make it perfect and the noble demeanor of evolution.It is the anti-evolutionist Leyle who, through a reductionist treatment, breaks down the evolutionary movement into its basic components—species that make the crucial contribution to the theory of evolution.Lyell believed that it was never possible to draw well-reasoned conclusions about the history of living things so long as the dispute was confined to general theories such as progress, tendencies toward perfection, and so on (as Lamarck did).Lyell believes that the biological world is composed of species. If there is evolution, as Lamarck said, species are the agents of evolution.Therefore, the problem of evolution cannot be solved by general arguments, but can only be illustrated by studying specific species, their origin, and their extinction.He had asked some specific questions about this: Are species fixed or variable?If fixed, can each species be traced back to a single origin in time and space?Since species can become extinct, how is the lifespan of species determined?Can the extinction of species and the introduction of new species be observed and related to observed environmental factors? So Leyle asks an admiring barrage of well-placed and to-the-point questions.These are the questions that Darwin and Wallace explored diligently in the ensuing decades.Lyell himself is a true essentialist who consistently gives wrong answers to the questions he asks.For him, patterns begin and patterns die. The origin and extinction of species are two sides of the same coin.He never understood (at least until Darwin and Wallace pointed it out to him) that the evolution of a new species of population and the extinction of the last survivors of a decaying species were two entirely different processes. By the 1820s, almost all geologists agreed that many species had become extinct over time, replaced by new ones.Several interesting theories were put forward to explain the extinction of species and the appearance of new ones.Some geologists believe that extinctions are catastrophic, and in extreme cases are the result of repeated destruction of all previous creations by the creator. Agassiz, for example, believes this explanation.It has also been suggested that species disappear individually because their lifespan has reached the end of their lifespan or because the environment is no longer suitable.Crucial to the development of Darwin's theory was Lyell's choice of this last argument and his contribution to the natural history of fauna and flora by directing attention to ecology and geography. Lyell's Principles of Geology became Darwin's "bible" as far as evolution was concerned.There is good evidence that Darwin accepted Lyell's conclusions without question for most of the Beagle's voyage.Both Lyell and Lamarck started from the same two observations: that species live in environments that are constantly (but slowly) changing; and that species are very adaptable to the environments in which they live.Yugan Lamarck believed that extinction of species was impossible, so he concluded that species must undergo continuous evolutionary changes in order to adapt to changes in their environment.Lyell was an essentialist and theist, who believed that species are fixed and therefore must die out if they cannot adapt to changes in their environment. Lyell's explanation for the extinction seems plausible.Here he advanced an important idea, which was then developed especially by Darwin: not only physical factors in the environment can cause extinction, but competition of other, more adapted species can also cause extinction.This interpretation is of course consistent with the view of the struggle for existence, which was widespread long before Darwin read Malthus. Lyell's explanation for the replacement of extinct species by new ones was far from successful.To stick to his uniformitarian principles, he assumes that new species are introduced at an essentially constant rate, but he offers neither evidence nor mechanism for this.因此他就将自己公开置于Bronn（《地质学原理》的一位德国评论者）的批判矛头下，后者指责他在生物方面背弃了均变论原则。莱伊尔（1881）在给他的一位朋友Herschel的信中企图为自己辩护，说什么有某些未知的中介原因可能和引进新种有关。 然而对引进新种的过程描述与任何可以想像的第二位原因都是互相抵触的：“物种可能是在这样的时间和这样的地点相继被创造出来的，使它们能够增殖并持续一段指定的时间并且在地球上占有指定的空间。”莱伊尔在这里反复使用“指定的”字样表明，就莱伊尔来说，每次创造都是仔细计划了的事态（Mayr，1972b）。这样坦白乞灵于超自然力使莱伊尔也感到某种程度的尴尬，但是他从Herschel的下述意见中倒能得到一丝安慰： “我们都完全相同地假定（造物主）通过一系列的中介原因进行操纵，其结局是新种的起源（如果我们能察觉的话）将会是一种自然过程，以别于神奇的不可思议的过程。” 作为一个数学家和天文学家，Herschel并不了解除了进化（我们现在知道还有某些染色体过程）以外并没有什么中介原因能够在正确的时间和正确的地点产生固定不变的物种。 Herschel和莱伊尔所设想的正是他们公开反对的那种不可思议的奇迹。当然，莱伊尔在别的地方也曾坦率地承认在神创论概念上他依附于“不断介入论”（Lyell，1970，复印版）。因此，达尔文在中花了很多篇幅来驳斥特创论是不足为怪的（Gillespie，1979）。 在本质论的基础上是根本不可能产生进化学说的。本质在时间上和空间上都是不可变的，是非因次（非量纲）现象。由于本质缺乏变异，它们就不能进化或萌发端始种。 莱伊尔设想指出新种将占有空闲位置（生境）他就解决了引入新种的问题。作为一个本质论者（和林奈相同），他是按引进单独一对配偶将未能成为新种的始祖的观点来理解物种形成的。有理由相信达尔文在1837年3月以前也具有类似的模式观点。这可以由他对南美三趾鸵鸟（Rhea）第二个鸟种来源的描述表明。物种形成这个问题的研究只有当博物学家认识到物种分类单位是因次（量纲）现象以后才有所进展。物种具有空间与时间的广延性；它们是有结构的、是由秤群组成的；而种群至少一部分（当它们被隔离后）是互相独立无关的。因此，和莱伊尔所坚持的相反，物种是变化的，每一个被隔离的物种种群就是一个端始种，是多样性起源的潜在来源。按照莱伊尔的论点，格拉帕戈斯岛上小嘲鸫（反舌鸟，或直译为模仿鸟）的空闲生境将由该岛小嘲鸫鸟种的“引入”（不论是通过什么方式）来占据。然而每个岛屿有其本身的物种这一点却是莱伊尔的机制所无法解释的。隔离（现象）和渐进进化却能解释它。这是达尔文从格拉帕戈斯岛上的鸟类区系所学习到的一课。 近年来进行了大量的研究工作来探索达尔文是怎样一步又一步地转变成为进化论者。 达尔文本人就这个问题所谈起的时间很容易引起误解。他在的绪论中用下面的一段话开头：“当我作为一个博物学家踏上贝格尔号后，我对南美洲动物的分布、南美洲现有动物和过去动物与地质的关系等方面的某些事实给我以极其深刻的印象。这些事实好像使我懂得了被一位着名的哲学家称之为至高无上的神秘的物种起源。”这就暗示他在贝格尔号南美洲航行阶段就已经是一个进化论者了，在他的自传中也有同样的说法。但是他的日记并不支持这一点。当他在格拉帕戈斯群岛上采集标本时，他确实是将不同岛屿上的标本都加上“格拉帕戈斯”的标志，根本没有考虑地理变异现象。当格拉帕戈斯岛上的官员告诉他每个海岛上的巨龟都有所不同时，他本应当了解这一点。但是，达尔文在格拉帕戈斯群岛上所见到的一切也足以使他大惑不解，当贝格尔号返航时（1836年7月？）他写下了如下的预见性评论：“当我看到这些岛屿彼此相距不远而且动物种类不多，住在岛上小鸟在体躯结构上只有很细微的差异并都栖息在同一个地方时，我就必然要猜想这些鸟是变种…如果这些议论稍微有点根据，那末格拉帕戈斯群岛的动物学就很值得研究，因为这些事实有可能削弱或破坏物种稳定性的基础”（Barlow，1963）。