Darwin's species category realism

Ever since Charles Darwin's On the Origin of Species was published, the received view has been that Darwin literally thought of species as not extra-mentally real. In 1969 Michael Ghiselin upset the received view by interpreting Darwin to mean that species taxa are indeed real but not the species category. In 1985 John Beatty took Ghiselin's thesis a step further by providing a strategy theory to explain why Darwin would say one thing (his repeated nominalistic definition of species) and do another (hold that species taxa are real). In the present paper I attempt to take this line of interpretation to a new level. Guided by the principle of charity, I provide and analyze a considerable amount of evidence from Darwin's mature writings (both private and published) to show that (contra Ghiselin and Beatty) Darwin did not simply accept the species delimitations of his fellow naturalists but actually employed, repeatedly and consistently, a species concept in a thoroughly modern sense, albeit with an implicit definition, a concept uniquely his own and fully in accord with his theory of evolution by natural selection. This implicit concept and definition is carefully reconstructed in the present paper. A new strategy theory is then provided to account for why Darwin would define species (both taxa and category) nominalistically on the one hand but delimit species realistically on the other.     

Darwin was a teleologist

It is often claimed that one of Darwin's chief accomplishments was to provide biology with a non-teleological explanation of adaptation. A number of Darwin's closest associates, however, and Darwin himself, did not see it that way. In order to assess whether Darwin's version of evolutionary theory does or does not employ teleological explanation, two of his botanical studies are examined. The result of this examination is that Darwin sees selection explanations of adaptations as teleological explanations. The confusion in the nineteenth century about Darwin's attitude to teleology is argued to be a result of Darwin's teleological explanations not conforming to either of the dominant philosophical justifications of teleology at that time. Darwin's explanatory practices conform well, however, to recent defenses of the teleological character of selection explanations.I would like to thank John Beatty, David Hull and one of this journal's readers for constructive comments on an earlier draft of this paper.     

Was Darwin a creationist?

Throughout the Origin of Species, Darwin contrasts his theory of natural selection with the theory that God independently created each species. This makes it seem as though the Origin offers a scientific alternative to a theological worldview. A few months after the Origin appeared, however, the eminent anatomist Richard Owen published a review that pointed out the theological assumptions of Darwin's theory. Owen worked in the tradition of rational morphology, within which one might suggest that evolution occurs by processes that are continuous with those by which life arises from matter; in contrast, Darwin rested his account of life's origins on the notion that God created one or a few life forms upon which natural selection could act. Owen argued that Darwin's reliance on God to explain the origins of life makes his version of evolution no less supernatural than the special creationist that Darwin criticizes: although Darwin limits God to one or a few acts of creation, he still relies upon God to explain life's existence.     

Evolution in fossil lineages: paleontology and The Origin of Species

Of all of the sources of evidence for evolution by natural selection, perhaps the most problematic for Darwin was the geological record of organic change. In response to the absence of species-level transformations in the fossil record, Darwin argued that the fossil record was too incomplete, too biased, and too poorly known to provide strong evidence against his theory. Here, this view of the fossil record is evaluated in light of 150 years of subsequent paleontological research. Although Darwin's assessment of the completeness and resolution of fossiliferous rocks was in several ways astute, today the fossil record is much better explored, documented, and understood than it was in 1859. In particular, a reasonably large set of studies tracing evolutionary trajectories within species can now be brought to bear on Darwin's expectation of gradual change driven by natural selection. An unusually high-resolution sequence of stickleback-bearing strata records the transformation of this lineage via natural selection. This adaptive trajectory is qualitatively consistent with Darwin's prediction, but it occurred much more rapidly than he would have guessed: almost all of the directional change was completed within 1,000 generations. In most geological sequences, this change would be too rapid to resolve. The accumulated fossil record at more typical paleontological scales (10(4)-10(6) years) reveals evolutionary changes that are rarely directional and net rates of change that are perhaps surprisingly slow, two findings that are in agreement with the punctuated-equilibrium model. Finally, Darwin's view of the broader history of life is reviewed briefly, with a focus on competition-mediated extinction and recent paleontological and phylogenetic attempts to assess diversity dependence in evolutionary dynamics.     

Darwin's artificial selection as an experiment

Darwin used artificial selection (ASN) extensively and variedly in his theorizing. Darwin used ASN as an analogy to natural selection; he compared artificial to natural varieties, hereditary variation in nature to that in the breeding farm; and he also compared the overall effectiveness of the two processes. Most historians and philosophers of biology have argued that ASN worked as an analogical field in Darwin's theorizing. I will argue rather that this provides a limited and somewhat muddled view of Darwinian science. I say "limited" because I will show that Darwin also used ASN as a complex experimental field. And I say "muddled" because, if we concentrate on the analogical role exclusively, we conceive Darwinian science as rather disconnected from contemporary conceptions of "good science". I will argue that ASN should be conceived as a multifaceted experiment. As a traditional experiment, ASN established the efficacy of Darwin's preferred cause: natural selection. As a non-traditional experiment, ASN disclosed the nature of a crucial element in Darwin's evolutionary mechanics: the nature of hereditary variation. Finally, I will argue that the experiment conception should help us make sense of Darwin's comments regarding the "monstrous" nature of domestic breeds traditionally considered to be problematic.     

Darwin's laws

There is widespread agreement among contemporary philosophers of biology and philosophically-minded biologists that Darwin's insights about the intrusion of chance processes into biological regularities undermines the possibility of there being biological laws. Darwin made references to "designed laws." He also freely described some laws as having exceptions. This paper provides a philosophical analysis of the notion of scientific laws that was dominant in Darwin's time, and in all probability the one which he inherited. The analysis of laws is then used to show how it could have been natural for Darwin to believe in designed laws that had exceptions, and to highlight the continuity between the metaphysics of pre-Darwinian, Darwinian, and contemporary biological science. One important result is the removal of one motivation for the anti-laws sentiment in philosophy and biology.     

The historical context of natural selection: The case of Patrick Matthew

Conclusions It should be evident from the foregoing discussion that one man's natural selection is not necessarily the same as another man's. Why should this be so? How can two theories, which both Matthew and Darwin believed to be nearly identical, be so dissimilar? Apparently, neither Matthew nor Darwin understood the other's theory. Each man's viewpoint was colored by his own intellectual background and philosophical assumptions, and each read these into the other's ideas. The words sounded the same, so they assumed the concepts must als be the same.¹²³ As Ghiselin has pointed out, historians attempting to evaluate Darwin's predecessors have been similarly blinded by a preoccupation with words, without regard to their proper context.¹²⁴ In the case of Matthew, the practice of quoting only brief passages from the appendix to Naval Timber and Arboriculture, without relating them to the rest of his work, has suggested a greater resemblance to Darwin's theory than actually exists.It is clear, both from the use which Matthew made of his ideas and from the philosophical roots of his natural world view, that he could not have arrived at the concept of natural selection by the same thought process which Darwin employed. His discussion of natural selection is presented not as an argument, but as an axiom. No theory is proposed, no evidence marshaled to support it. Natural selection is stated as a fact, a Law of Nature, unquestioned, and presumably, unquestionable.Despite his clamor for recognition as the discoverer of natural selection, Matthew recognized and acknowledged this very fundamental difference between Darwin and himself. In a letter to the Gardener's Chronicle of May 12, 1860, he wrote:To me the conception of this law of Nature came intuitively as a self-evident fact, almost without an effort of concentrated thought. Mr. Darwin here seems to have more merit in the discovery than I have had—to me it did not appear a discovery. He seems to have worked it out by inductive reason, slowly and with due caution to have made his way synthetically from fact to fact onwards; while with me it was by a general glance at the scheme of Nature that I estimated this select production of species as an a priori recognisable fact—an axiom, requiring only to be pointed out to be admitted by unprejudiced minds of sufficient grasp.¹²⁵ In the same letter, Matthew maintained that his ideas had not been accepted because the age was not ripe for such ideas.¹²⁶ Nor, he said, was the present age. He considered the inability of most of Darwin's critics to grasp his theory to be incurable. Yet he did not argue that natural selection should be accepted because of the evidence, but rather, that it should be accepted on faith:Belief here requires a certain grasp of mind. No direct proof of phenomena embracing so long a period of time is within the compass of short-lived man. To attempt to satisfy a school of ultra skeptics, who have a wonderfully limited power of perception of means to ends... would be labour in vain.... They could not be brought to conceive the purpose of a handsaw though they saw its action, if the whole individual building it assisted to construct were not presented complete before their eyes... Like a child looking upon the motion of a wheel in an engine they would only perceive and admire... without noticing its agency in... affecting the purposed end.¹²⁷ Here, then, is the final irony. In a passage urging acceptance of Darwin's theory, a theory which was to banish design and purpose from the natural world, we find echoes of Paley and of Providence.Loren Eiseley has lamented the fact that Matthew did not bring his views into the open, because the amount of ground he was able to cover in a few paragraphs suggests that he might have been able to sustain a longer treatise.¹²⁸ Now that the intellectual and historical context of Matthew's ideas are known, this statement is no longer tenable. Matthew was not a scientist, and his books were not written as biological treatises. His discussions of natural selection were not attempts to cover ground in advancing a particular scientific theory, but were simply reflections of his own assumptions about the natural world.Furthermore, despite Matthew's acceptance of evolution and natural selection, his biological thought was basically conservative on points where Darwin's was radical. Where Matthew saw a series of stable worlds interrupted by violent upheavals, Darwin saw a continuous process of change in an ever-fluctuating world. Where Matthew conceived of species in terms of Aristotelian classes and essences, Darwin revolutionized our concept of species by treating them as populations. Where Matthew saw a world of design and beauty functioning according to natural laws laid down by benevolent Providence, Darwin abolished design and Providence from nature and ushered in a world which cycles ever onward according to laws of chance and probability.It is not even particularly useful to point to Matthew as evidence that evolution was in the air prior to 1859.¹²⁹ His ideas did not represent the first wave of a coming revolution, but were the product of his own personal philosophical outlook, as expressed in the context of the biological thought of the 1830's. Matthew is important in the history of ideas, not simply because he accepted the concept of evolution or thought of something resembling natural selection, but because he did so without overthrowing, in his own mind, any of the basic philosophical assumptions which had underlain biological science since Aristotle. In recognizing Matthew's failure to do so, we are in a position to appreciate more fully the significance of the Darwinian Revolution.     

Darwin's artificial selection analogy and the generic character of "phyletic" evolution

This paper examines the way Charles Darwin applied his domestic breeding analogy to the practical workings of species evolution: that application, it is argued, centered on Darwin's distinction between methodical and unconscious selection. Methodical selection, which entailed pairing particular individuals for mating purposes, represented conditions of strict geographic isolation, obviously useful for species multiplication (speciation). By contrast, unconscious selection represented an open landmass with a large breeding population. Yet Darwin held that this latter scenario, which often would include multiple ecological subdistricts and thus partial isolation, was better suited for speciation than were isolated conditions. At the same time, many passages in Darwin's writings that apparently portrayedphyletic evolution exclusively (these including references to unconscious selection), actually applied to speciation as well, for phyletic change in a single district could constitute a local manifestation of a larger common-descent pattern. This generic use of "phyletic" change was reflected in Darwin's deployment of the unconscious selection analogy in his published writings as well as in his dispute with Moritz Wagner over the necessity of geographic isolation for speciation. We can thus understand Darwin's otherwise puzzling declaration in The Origin of Species that unconscious selection was 'more important' than the methodical approach.     

Darwin's explanation of races by means of sexual selection

In Darwin's Sacred Cause, Adrian Desmond and James Moore contend that "Darwin would put his utmost into sexual selection because the subject intrigued him, no doubt, but also for a deeper reason: the theory vindicated his lifelong commitment to human brotherhood" (2009: p. 360). Without questioning Desmond and Moore's evidence, I will raise some puzzles for their view. I will show that attention to the structure of Darwin's arguments in the Descent of Man shows that they are far from straightforward. As Desmond and Moore note, Darwin seems to have intended sexual selection in non-human animals to serve as evidence for sexual selection in humans. However, Darwin's account of sexual selection in humans was different from the canonical cases that Darwin described at great length. If explaining the origin of human races was the main reason for introducing sexual selection, and if sexual selection was a key piece of Darwin's anti-slavery arguments, then it is puzzling why Darwin would have spent so much time discussing cases that did not really support his argument for the origin of human races, and it is also puzzling that his argument for the origin of human races would be so (atypically) poor.     

The genetics and evolution of female choice

Darwin based his theory of evolution on the central theme of 'the struggle for existence', 'the preservation of favoured races', 'the survival of the fittest'. In addition to this 'natural selection', he proposed a second type of selection, sexual selection. 'This depends, not on a struggle for existence, but on a struggle between males for possession of the females; the result is not death to the unsuccessful competitor, but few or no offspring. Males would compete for females, and females would choose between males. Since Darwin's work, many examples of natural selection have been observed in nature and in laboratory experiments, and knowledge of genetics has given natural selective theory a sound basis. The theory of sexual selection through male competition has also been widely accepted. However, the theory of sexual selection through female choice has had a much more chequered passage.     

"Curiously parallel": analogies of language and race in Darwin's Descent of man. A reply to Gregory Radick

In the second chapter of The descent of man (1871), Charles Darwin interrupted his discussion of the evolutionary origins of language to describe ten ways in which the formation of languages and of biological species were 'curiously' similar. I argue that these comparisons served mainly as analogies in which linguistic processes stood for aspects of biological evolution. Darwin used these analogies to recapitulate themes from On the origin of species (1859), including common descent, genealogical classification, the struggle for existence, and natural selection, among others. Skeptical of this interpretation, Gregory Radick sees the naturalistic account of language formation in the Descent comparisons as reinforcing Darwin's idea that languages and the races of mankind have both undergone progressive development. (The opposite view was that modern-day primitive peoples had degenerated from an originally civilized condition.) Yet the details of Darwin's language-species comparisons, as well as the polemical context in which they appear, show that they were not aimed at so limited a function. Rather, they addressed issues related to species transmutation in general.     

Zum konzept der »inneren« selektion: Stellungnahme zu einer evolutionstheoretischen kontroverse

Recently the concept of natural selection in Darwin’s sense has been criticized by some authors. It has been argued that this concept does not explain certain phenomena of evolutionary change, especially in the reach of macroevolution. Some biologists, therefore, demanded for evolution a new model of selection which focuses internal factors in phytogeny. — This paper is a brief discussion of some aspects of “internal” selection and its meaning in contemporary evolutionary biology. The argument of the paper is that evolution can only be explained by a theory taking cognizance of interactions between external and internal selective agencies. Such a theory would be a systems theory of evolution.     

God and natural selection: The Darwinian idea of design

Conclusion If we arrange in chronological order the various statements Darwin made about God, creation, design, plan, law, and so forth, that I have discussed, there emerges a picture of a consistent development in Darwin's religious views from the orthodoxy of his youth to the agnosticism of his later years. Numerous sources attest that at the beginning of the Beagle voyage Darwin was more or less orthodox in religion and science alike.⁷⁸ After he became a transmutationist early in 1837, he concluded that the doctrine of secondary causes must be extented even to the history of life and that after the first forms of life were created, there was no further need for divine intervention, except where man was concerned. Man's body, he thought, was produced by the process of transmutation, but he believed for a time that man's soul was superadded. By mid-1838 he had become convinced that nothing, after the creation of life, was due to miracles. God works only through laws, which are capable of producing every effect of evey kind which surrounds us. The existence of man, the idea of God in man's mind, and the harmony of the whole system were in his eyes prearranged goals of deterministic laws imposed by God. Such a conception excludes the miracles on which Christianity depends; but it is not possible to say whether Darwin's loss of Christian faith, which occurred at about this same time, preceded and made possible his materialism or was rather caused or hastened by it.⁷⁹ In the weeks after his reading of Malthus, Darwin's belief in a plan of creation gave way to the belief that God created matter and life and designed their laws, leaving the details, however, to the workings of chance. This remained his view until the 1860s.There is no exact parallel between this development of Darwin's religious views and the development of his ideas on evolution, but there is a general correspondence. When he believed in a plan of creation, Darwin's theory of transmutation did not depend on struggle or the selection of chance variations. Adaptation was, for him, an automatic response to environmental chance. From late 1838 to 1859 he believed in designed laws and chance, and this belief, too, has its parallel in his theory. The element of chance in natural selection meant that there could be no detailed plan,in which even man's idea of God would be a necessary outcome of nature's laws (man himself is not a necessary outcome of the working of natural selection).⁸⁰ But Darwin still believed nature was programmed to achieve certain general ends. We might say that he believed in a general, though not a special, teleology. Natural selection was for him a law to maximize utility, creating useful organs, retaining vestiges for future use. For many years it was a law designed to produce organisms perfectly adapted to their environments. Only later did Darwin come to doubt even this sort of design in nature.⁸¹ One way of describing the development of Darwin's evolutionary thought is to say that it shows a gradual abandoning of his theistic assumptions, so that by the late 1860s his theory was informed to a slighter extent by notions of purpose and design than it was in 1838 or 1844 or 1859.     

Two Explanations of Evolutionary Progress

Natural selection explains how living forms are fitted to theirconditions of life. Darwin argued that selection also explains what hecalled the gradual advancement of the organisation, i.e.evolutionary progress. Present-day selectionists disagree. In theirview, it is happenstance that sustains conditions favorable to progress,and therefore happenstance, not selection, that explains progress. Iargue that the disagreement here turns not on whether there exists aselection-based condition bias – a belief now attributed to Darwin – but on whether there needs to be such a bias for selection to count as explaining progress. In Darwin's own view, selection explained progressso far as more complex organisms have the selective advantage whenselection operates unimpeded. I show that these two explanations ofevolutionary progress, selection and happenstance, answer for theirobjectivity to different standards, and for their truth or falsehood todifferent features of the world.     

Charles Darwin and the problem of evolutionary progress

According to Ch. Darwin's evolutionary theory, evolutionary progress (interpreted as morpho-physiological progress or arogenesis in recent terminology) is one of logical results of natural selection. At the same time, natural selection does not hold any factors especially promoting evolutionary progress. Darwin emphasized that the pattern of evolutionary changes depends on organism nature more than on the pattern of environment changes. Arogenesis specificity is determined by organization of rigorous biological systems - integral organisms. Onward progressive development is determined by fundamental features of living organisms: metabolism and homeostasis. The concept of social Darwinism differs fundamentally from Darwin's ideas about the most important role of social instincts in progress of mankind. Competition and selection play secondary role in socio-cultural progress of human society.     

Phylogenetic inertia and Darwin's higher law

The concept of 'phylogenetic inertia' is routinely deployed in evolutionary biology as an alternative to natural selection for explaining the persistence of characteristics that appear sub-optimal from an adaptationist perspective. However, in many of these contexts the precise meaning of 'phylogenetic inertia' and its relationship to selection are far from clear. After tracing the history of the concept of 'inertia' in evolutionary biology, I argue that treating phylogenetic inertia and natural selection as alternative explanations is mistaken because phylogenetic inertia is, from a Darwinian point of view, simply an expected effect of selection. Although Darwin did not discuss 'phylogenetic inertia,' he did assert the explanatory priority of selection over descent. An analysis of 'phylogenetic inertia' provides a perspective from which to assess Darwin's view.     

A case reopened: teleology and its consequences for the units of selection discussion.

Darwinian explanations for teleology are often imprecise, and justify the occurrence of teleological features by referring to natural selection in a vague and unspecified sense. In this paper, the Darwinian account for teleology is further analyzed. It is argued that in theory only a specific form of teleology--teleology that is caused by and directed towards the preservation of the genetic program--can be explained in a naturalistic way by employing Darwin's theory of natural selection. This observation links teleology with the units of selection discussion, as for both discussions the end-direction of teleological processes and behavior is of elementary importance. According to Dawkins' analysis, the unit of selection is an active germ-like replicator with a sufficient degree of longevity-fecundity-copying fidelity. From the teleological point of view, the unit of selection should additionally incorporate the genetic program in order to naturalize teleology. It is shown that within sexually reproducing species these two requirements cannot be met. Dawkins' concept of genic selectionism cannot be maintained without violating the naturalistic claims on teleology, and none of the other frequently proposed unit of selection candidates can adequately meet the demands as developed by Dawkins and those developed in the light of teleology.     

Darwin and the origin of interspecific genetic incompatibilities

Darwin's Origin of Species is often criticized for having little to say about speciation. The complaint focuses in particular on Darwin's supposed failure to explain the evolution of the sterility and inviability of interspecific hybrids. But in his chapter on hybridism, Darwin, working without genetics, got as close to the modern understanding of the evolution of hybrid sterility and inviability as might reasonably be expected. In particular, after surveying what was then known about interspecific crosses and the resulting hybrids, he established two facts that, while now taken for granted, were at the time radical. First, the sterility barriers between species are neither specially endowed by a creator nor directly favored by natural selection but rather evolve as incidental by-products of interspecific divergence. Second, the sterility of species hybrids results when their development is "disturbed by two organizations having been compounded into one." Bateson, Dobzhansky, and Muller later put Mendelian detail to Darwin's inference that the species-specific factors controlling development (i.e., genes) are sometimes incompatible. In this article, I highlight the major developments in our understanding of these interspecific genetic incompatibilities--from Darwin to Muller to modern theory--and review comparative, genetic, and molecular rules that characterize the evolution of hybrid sterility and inviability.     

Ecological aspects of the evolutionary processes

Darwin in his On the Origin of species made it clear that evolutionary change depends on the combined action of two different causes, the first being the origin of genetically based phenotypic variation in the individual organisms comprising the population and the second being the action of selective agents of the external environment placing demands on the individual organisms. For over a century following Darwin, most evolutionists focused on the origin of inherited variation and its transmission; many workers continue to regard genetics to be the core of evolutionary theory. Far less attention has been given to the exact nature of the selective agents with most evolutionists still treating this cause imprecisely to the detriment of our understanding of both nomological and historical evolutionary theory. Darwin was vague in the meaning of his new concept of "Natural Selection," using it interchangeably as one of the causes for evolutionary change and as the final outcome (= evolutionary change). In 1930, natural selection was defined clearly as "non-random, differential reproduction of genes" by R. Fisher and J.B.S. Haldane which is a statement of the outcome of evolutionary process and which omits mention of the causes bringing about this change. Evolutionists quickly accepted this outcome definition of natural selection, and have used interchangeably selection both as a cause and as the result of evolutionary change, causing great confusion. Herein, the details will be discussed of how the external environment (i.e., the environment-phenotype interaction) serves as selective agents and exerts demands on the phenotypic organisms. Included are the concepts of fitness and of the components of fitness (= adaptations) which are respectively (a) survival, (b) direct reproductive and (c) indirect reproductive features. Finally, it will be argued that historical-narrative analyses of organisms, including classification and phylogenetic history, are possible only with a full understanding of nomological evolutionary theory and with functional/adaptive studies of the employed taxonomic features in addition to the standard comparative investigations.     

Darwin and the linguists: the coevolution of mind and language, part 2. The language-thought relationship

This paper examines Charles Darwin's idea that language-use and humanity's unique cognitive abilities reinforced each other's evolutionary emergence-an idea Darwin sketched in his early notebooks, set forth in his Descent of man (1871), and qualified in Descent's second (1874) edition. Darwin understood this coevolution process in essentially Lockean terms, based on John Locke's hints about the way language shapes thinking itself. Ironically, the linguist Friedrich Max Müller attacked Darwin's human descent theory by invoking a similar thesis, the German romantic notion of an identity between language and thought. Although Darwin avoided outright contradiction, when he came to defend himself against Müller's attacks, he undercut some of his own argumentation in favor of the coevolution idea. That is, he found it difficult to counter Müller's argument while also making a case for coevolution. Darwin's efforts in this area were further complicated by British and American writers who held a naturalistic view of speech origins yet still taught that language had been invented by fully evolved homo sapiens, thus denying coevolution.