After clarifying how Darwin understood natural selection and common ancestry, I consider how the two concepts are related in his theory. I argue that common ancestry has an evidential priority. For Darwin, arguments about natural selection often make use of the assumption of common ancestry, whereas defending common ancestry does not require the assumption that natural selection has been at work. In fact, Darwin held that the key evidence for common ancestry comes from characters whose evolution is not caused by (...) natural selection. This raises the question of why Darwin puts natural selection first and foremost in the Origin. (shrink)

Are species real categories or just conventions? Are species natural kinds? Are teleological statements a distinctive feature of biology? Can life sciences escape from teleology? These are common issues in philosophy of biology. This paper aims to show that in order to answer to each of these questions it is inevitable to take a position respecting the others. Therefore, there is a historical relation between the concept of species and teleological issues. In order to analyse such relation, I will take (...) a historical perspective.After making such historical reconstruction focused on the Aristotle, Linnaeus, Buffon and Lamarck thoughts, I will analyse the Darwinian peculiar view respect teleology and his ideas about species. Although Darwin set out the collapse of teleological essentialisms in biology, there are important vestiges of teleology in his theory. (shrink)

Historians tend to speak of the problem of the origin of species or the species question, as if it were a monolithic problem. In reality, the phrase refers to a, historically, surprisingly fluid and pluriform scientific issue. It has, in the course of the past five centuries, been used in no less than ten different ways or contexts. A clear taxonomy of these separate problems is useful or relevant in two ways. It certainly helps to disentangle confusions that have inevitably (...) emerged in the literature in its absence. It may, secondly, also help us to gain a more thorough understanding, or sharper view, of the history of evolutionary thought. A consequent problem-centric look at that history through the lens of various origin of species problems certainly yields intriguing results, including and particularly for our understanding of the genesis of the Wallace–Darwin theory of evolution through natural selection. (shrink)

Historians and philosophers of science agree that Darwin had an understanding of species which led to a workable theory of their origins. To Darwin species did not differ essentially from ‘varieties’ within species, but were distinguishable in that they had developed gaps in formerly continuous morphological variation. Similar ideas can be defended today after updating them with modern population genetics. Why then, in the 1930s and 1940s, did Dobzhansky, Mayr and others argue that Darwin failed to understand species and speciation? (...) Mayr and Dobzhansky argued that reproductively isolated species were more distinct and ‘real’ than Darwin had proposed. Believing species to be inherently cohesive, Mayr inferred that speciation normally required geographic isolation, an argument that he believed, incorrectly, Darwin had failed to appreciate. Also, before the sociobiology revolution of the 1960s and 1970s, biologists often argued that traits beneficial to whole populations would spread. Reproductive isolation was thus seen as an adaptive trait to prevent disintegration of species. Finally, molecular genetic markers did not exist, and so a presumed biological function of species, reproductive isolation, seemed to delimit cryptic species better than character-based criteria like Darwin’s. Today, abundant genetic markers are available and widely used to delimit species, for example using assignment tests: genetics has replaced a Darwinian reliance on morphology for detecting gaps between species. In the 150th anniversary of The Origin of Species , we appear to be returning to more Darwinian views on species, and to a fuller appreciation of what Darwin meant. (shrink)

Aristotle’s influence on D’Arcy Thompson was praised by Thompson himself and has been recognized by others in various respects, including the aesthetic and normative dimensions of biology, and the multicausal explanation of living forms. This article focuses on the relatedness of organic forms, one of the core problems addressed by both Aristotle’s History of Animals (HA), and the renowned chapter of Thompson’s On Growth and Form (G&F), “On the Theory of Transformations, or the Comparison of Related Forms.” We contend that, (...) far from being an incidental inspiration stemming from Thompson’s classicist background, his translation of HA played a pivotal role in developing his theory of transformations. Furthermore, we argue that Thompson’s interpretation of the Aristotelian method of comparison challenges the prevailing view of Aristotle as the founder of “typological essentialism,” and is a key episode in the revision of this narrative. Thompson understood that the method Aristotle used in HA to compare animal forms is better comprehended as a “method of transformations,” leading to a morphological arrangement of animal diversity, as opposed to a taxonomical classification. Finally, we examine how this approach to the relatedness of forms lay the foundation for a causal understanding of parts and their interconnections. Although Aristotle and Thompson emphasized distinct types of causes, we contend that they both differ in a fundamental sense from the one introduced by Darwin’s theory of natural selection, which was formulated as a solution to the species problem rather than the form problem. We conclude that Thompson’s interpretation of Aristotle’s approach to form comparison has not only impacted contemporary scholarship on Aristotle’s biology, but revitalized a perspective that has regained significance due to the resurgence of the problem of form in evo-devo. (shrink)

ABSTRACTThe historical process underlying Darwin’s Origin of Species did not play a significant role in the early editions of the book, in spite of the particular inductivist scientific methodology it espoused. Darwin’s masterpiece did not adequately provide his sources or the historical perspective many contemporary critics expected. Later editions yielded the ‘Historical Sketch’ lacking in the earlier editions, but only under critical pressure. Notwithstanding the sources he provided, Darwin presented the Origin as an ‘abstract’ in order to avoid giving sources; (...) a compromise he acknowledged and undertook to set right in later editions, yet failed to provide throughout the six editions under his supervision. Darwin’s reluctance to publish the historical context of his theory and his sources, particularly sources which were also ‘precursors’, may be attributed as much to the matter of intellectual ownership as science, or even good literary practice. Of special concern to Darwin were issues of priority or originality over ‘descent with modification’ and especially over Natural Selection. Many later historians have argued that Darwin was unaware of the work of his precursors on Natural Selection. Darwin’s theory was an example of independent discovery, albeit along with such obscure precursors as Matthew or Wells, who were unknown to Darwin until after the publication of the Origin. Both Matthew and Wells had a medical education, like James Hutton or Erasmus Darwin earlier in the eighteenth century, or even Charles Darwin. Evolutionary theory, at least in Britain was a product largely of the medical evolutionists rather than the natural historians which ‘history’ has chosen to select for the focus of attention; and among the medical evolutionists the figure of John Hunter stands out as theorist, experimentalist and teacher: the medical evolutionists were predominantly the product of Hunter’s legacy or of the medical profession and particularly the Scottish Universities. Much recent Darwin scholarship has focused on the private Notebooks, to establish Darwin’s discovery of Natural Selection around 1837–1838 and demonstrate Darwin’s ignorance of his precursors; requiring an explicit acknowledgement by Darwin as the legitimate substantiation of any claim to prior influence. The precursors have been categorized as uniformly obscure or irrelevant to the science of evolution which may be defined exclusively as ‘Darwinian’. The inclination to acknowledge influences, however was not something Darwin was gratuitously given to doing, especially on matters of priority. The Notebooks are not Darwin’s private thoughts; from an early stage he considered them incipient public documents and later sought to protect them as proof of his originality. William C. Wells was not an obscure thinker, but a celebrated scientist whom Herschel, Darwin’s guide to scientific methodology, had recommended as providing a model of scientific method. Darwin discovered Wells through Herschel, and quickly acquired a copy of Wells’ recommended work, no later than 1831, and held it thereafter in his library at Down House. This book, the 1818 edition of Wells’ Two Essays contains a third essay, Wells’ account of Natural Selection. Later, in the Descent of Man Darwin acknowledged his separate discovery of the correlation of colour and disease immunity in man, also earlier recounted by Wells. (shrink)

References in Darwin’s Origin of Species to competition between units of selection at and above the level of individual organisms are enumerated. In many cases these references clearly speak of natural selection and do not support the view that Darwin thought selection only occurred at the level of the individual organism. Darwin did see organismal selection as the main process by which varieties were created but he also espoused what is here termed community and varietal selection. He saw no essential (...) difference between varieties and species and the references show that he also believed that selection could operate at the species level. (shrink)