John Wilkins

Essentialism in philosophy is the position that things, especially kinds of things, have essences, or sets of properties, that all members of the kind must have, and the combination of which only members of the kind do, in fact, have. It is usually thought to derive from classical Greek philosophy and in particular from Aristotle’s notion of “what it is to be” something. In biology, it has been claimed that pre-evolutionary views of living kinds, or as they are sometimes called, “natu-ral kinds”, are essentialist. This static view of living things presumes that no tran-sition is possible in time or form between kinds, and that variation is regarded as accidental or inessential noise rather than important information about taxa. In contrast it is held that Darwinian, and post-Darwinian, biology relies upon varia-tion as important and inevitable properties of taxa, and that taxa are not, therefore, kinds but historical individuals. Recent attempts have been made to undercut this account, and to reinstitute essentialism in biological kind terms. Others argue that essentialism has not ever been a historical reality in biology and its predecessors. In this chapter, I shall outline the many meanings of the notion of essentialism in psychology and social science as well as science, and discuss pro- and anti-essentialist views, and some recent historical revisionism. It turns out that nobody was essentialist to speak of in the sense that is antievolutionary in biology, and that much confusion rests on treating the one word, “essence” as meaning a single notion when in fact there are many. I shall also discuss the philosophical implica-tions of essentialism, and what that means one way or the other for evolutionary biology. Teaching about evolution relies upon narratives of change in the ways the living world is conceived by biologists. This is a core narrative issue.

The longstanding species problem in biology has a history that suggests a solution, and that history is not the received history found in many texts written by biologists or philosophers. The notion of species as the division into subordinate groups of any generic predicate was the staple of logic from Aristotle through the middle ages until quite recently. However, the biological species concept during the same period was at first subtly and then overtly different. Unlike the logic sense, which relied on definitions of the essence of both genus and species, biological species from the time of Epicurus were consistently considered to involve a reproductive element: in short, living species relied not on essential definitions, but on the generative cause, which might not be definable. I term this the generative conception of species: species were the generation by reproduction of form. This undercuts the claim that species before Darwin were essentialist, and divorces the notion of a type from that of essence. In fact, as late as the end of the nineteenth century, logicians explicitly treated biological “species” as a homonym only of logical essentialist species, and permitted considerable deviation from the type or form. At every point, species in logic were thought to be a subset, in effect, of some more general notion. I sketch a history of both philosophical and biological traditions of the species concept, before turning to the current conceptions. These are reconsidered in the light of this history, and in particular Mayr’s changing views are shown to be somewhat Whiggish, historiographically. Of the many touted biological species concepts, only one of which (Mayr’s) is called _the_ Biological Species Concept, none appears to capture all the relevant facts, intuitions, and operational requirements of biology. Cladistic conceptions, however, have much in common with the older philosophical literature, in that the natural group of cladism is the clade, or monophyletic group. After considering the Individuality Thesis, and the metaphysics of species, we see that species are the most particular terminal taxa in a clade, and that they are “defined” in terms of the particular synapomorphies, or evolved characters, that are causally responsible for keeping the lineages that organisms form distinct from one another. In this way, we can remain within the generative conception of species that has been in play for over two millennia, and yet avoid the pitfalls of prior attempts to find a universal conception of species.

Ever since Darwin people have worried about the sceptical implications of evolution. If our minds are products of evolution like those of other animals, why suppose that the beliefs they produce are true, rather than merely useful? We consider this problem for beliefs in three different domains: religion, morality, and commonsense and scientific claims about matters of empirical fact. We identify replies to evolutionary scepticism that work in some domains but not in others. One reply is that evolution can be expected to design systems that produce true beliefs in some domain. This reply works for commonsense beliefs and can be extended to scientific beliefs. But it does not work for moral or religious beliefs. An alternative reply which has been used defend moral beliefs is that their truth does not consist in their tracking some external state of affairs. Whether or not it is successful in the case of moral beliefs, this reply is less plausible for religious beliefs. So religious beliefs emerge as particularly vulnerable to evolutionary debunking.

Ever since Darwin people have worried about the sceptical implications of evolution. If our minds are products of evolution like those of other animals, why suppose that the beliefs they produce are true, rather than merely useful? In this chapter we apply this argument to beliefs in three different domains: morality, religion, and science. We identify replies to evolutionary scepticism that work in some domains but not in others. The simplest reply to evolutionary scepticism is that the truth of beliefs in a certain domain is, in fact, connected to evolutionary success, so that evolution can be expected to design systems that produce true beliefs in that domain. We call a connection between truth and evolutionary success a ‘Milvian bridge’, after the tradition which ascribes the triumph of Christianity at the battle of the Milvian bridge to the truth of Christianity. We argue that a Milvian bridge can be constructed for commonsense beliefs, and extended to scientific beliefs, but not to moral and religious beliefs. An alternative reply to evolutionary scepticism, which has been used defend moral beliefs, is to argue that their truth does not depend on their tracking some external state of affairs. We ask if this reply could be used to defend religious beliefs.

This chapter distinguishes between two mindsets about science—the deductivist mindset and inductivist mindset—and explores the cognitive styles relating to authority and tradition in both science and pseudoscience. The deductivist tends to see problems as questions to be resolved by deduction from known theory or principle. The inductivist sees problems as questions to be resolved by discovery. Those leaning towards a deductivist mindset may find results that conflict with prior theoretical commitments unacceptable. The deductivist tends to be a cognitive conservative, and the inductivist a cognitive progressive. The conservative mindset more often leads to resentment about modernism and hence about certain scientific results.

To naturalize religion, we must identify what religion is, and what aspects of it we are trying to explain. In this paper, religious social institutional behavior is the explanatory target, and an explanatory hypothesis based on shared primate social dominance psychology is given. The argument is that various religious features, including the high status afforded the religious, and the high status afforded to deities, are an expression of this social dominance psychology in a context for which it did not evolve: high-density populations made possible by agriculture

Abstract Charles Darwin, in his discussions with Asa Gray and in his published works, doubted whether God could so arrange it that exactly the desired contingent events would occur to cause particular outcomes by natural selection. In this paper, I argue that even a limited or neo-Leibnizian deity could have chosen a world that satisfied some arbitrary set of goals or functions in its outcomes and thus answer Darwin's conundrum. In more general terms, this supports the consistency of natural selection with providentialism, and makes “theistic evolutionism” a coherent position to hold

Few problems in the philosophy of evolutionary biology are more widely disseminated and discussed than the charge of Darwinian evolution being a tautology. The history is long and complex, and the issues are many, and despite the problem routinely being dismissed as an introductory-level issue, based on misunderstandings of evolution, it seems that few agree on what exactly these misunderstandings consist of. In this paper, I will try to comprehensively review the history and the issues. Then, I will try to present the following “solution”, or, one might say, “dissolution”, of the problem, and consider the wider implications of formal, or schematic, explanations in science: yes, the principle of natural selection is a tautology, and so what? It is a promissory note for actual, physical, explanations in particular cases, and is none the worse for that. This is not a new argument, of course, but it does point up the importance of formal schematic models in science.

Genes are thought to have evolved from long-lived and multiply-interactive molecules in the early stages of the origins of life. However, at that stage there were no replicators, and the distinction between interactors and replicators did not yet apply. Nevertheless, the process of evolution that proceeded from initial autocatalytic hypercycles to full organisms was a Darwinian process of selection of favourable variants. We distinguish therefore between Neo-Darwinian evolution and the related Weismannian and Central Dogma divisions, on the one hand, and the more generic category of Darwinian evolution on the other. We argue that Hull’s and Dawkins’ replicator/interactor distinction of entities is a sufficient, but not necessary, condition for Darwinian evolution to take place. We conceive the origin of genes as a separation between different types of molecules in a thermodynamic state space, and employ a notion of reproducers

The vision of natural kinds that is most common in the modern philosophy of biology, particularly with respect to the question whether species and other taxa are natural kinds, is based on a revision of the notion by Mill in A System of Logic. However, there was another conception that Whewell had previously captured well, which taxonomists have always employed, of kinds as being types that need not have necessary and sufficient characters and properties, or essences. These competing views employ different approaches to scientific methodologies: Mill’s class-kinds are not formed by induction but by deduction, while Whewell’s type-kinds are inductive. More recently, phylogenetic kinds (clades, or monophyletic-kinds) are inductively projectible, and escape Mill’s strictures. Mill’s version represents a shift in the notions of kinds from the biological to the physical sciences.

We argue that the logical outcome of the cladistics revolution in biological systematics, and the move towards rankless phylogenetic classification of nested monophyletic groups as formalized in the PhyloCode, is to eliminate the species rank along with all the others and simply name clades. We propose that the lowest level of formally named clade be the SNaRC, the Smallest Named and Registered Clade. The SNaRC is an epistemic level in the classification, not an ontic one. Naming stops at that level because there is no currently acceptable evidence for clades within it, not because no smaller clades exist. Later, included clades may be named. They would then become the SNaRCs, while the original SNaRC would keep its original name. We argue that all theoretical tasks of biology, in evolution and ecology, as well as practical tasks such as conservation assessment, are better approached using this rankless phylogenetic approach.

Creationism is usually regarded as an irrational set of beliefs. In this paper I propose that the best way to understand why individual learners settle on any mature set of beliefs is to see that as the developmental outcome of a series of “fast and frugal” boundedly rational inferences rather than as a rejection of reason. This applies to those whose views are opposed to science in general. A bounded rationality model of belief choices both serves to explain the fact that folk traditions tend to converge on “anti-modernity”, and to act as a default hypothesis, deviations from which we can use to identify other, arational, influences such as social psychological, economic and individual dispositions. I propose some educational and public policy strategies that might decrease the proportion of learners who find creationism and anti-science in general a rational choice.

Scientists and philosophers routinely talk about phenomena, and the ways in which they relate to explanation, theory and practice in science. However, there are very few definitions of the term, which is often used synonymously with "data'', "model'' and in older literature, "hypothesis''. In this paper I will attempt to clarify how phenomena are recognized, categorized and the role they play in scientific epistemology. I conclude that phenomena are not necessarily theory-based commitments, but that they are what explanations are called to account for, which are not presently explained.

It is often claimed there is information in some biological entity or process, most especially in genes. Genetic “information” refers to distinct notions, either of concrete properties of molecular bonds and catalysis, in which case it is little more than a periphrasis for correlation and causal relations between physical biological objects (molecules), or of abstract properties, in which case it is mind-dependent. When information plays a causal role, nothing is added to the account by calling it “information”. In short, if genetic information is concrete, it is causality. If it is abstract, it is in the head.

Arguments against essentialism in biology rely strongly on a claim that modern biology abandoned Aristotle's notion of a species as a class of necessary and sufficient properties. However, neither his theory of essentialism, nor his logical definition of species and genus (eidos and genos) play much of a role in biological research and taxonomy, including his own. The objections to natural kinds thinking by early twentieth century biologists wrestling with the new genetics overlooked the fact that species have typical developmental cycles and most have a large shared genetic component. These are the "what-it-is-to-be" members of that species. An intrinsic biological essentialism does not commit us to Aristotelian notions, nor even modern notions, of essence. There is a long-standing definition of "species" and its precursor notions that goes back to the Greeks, and which Darwin and pretty well all biologists since him share, that I call the Generative Conception of Species. It relies on there being a shared generative power that makes progeny resemble parents. The "what-it-is-to-be" a member of that species is that developmental type, mistakes in development notwithstanding. Moreover, such "essences" have always been understood to include deviations from the type. Finally, I shall examine some implications of the collapse of the narrative about essences in biology.

The biological species (biospecies) concept applies only to sexually reproducing species, which means that until sexual reproduction evolved, there were no biospecies. On the universal tree of life, biospecies concepts therefore apply only to a relatively small number of clades, notably plants andanimals. I argue that it is useful to treat the various ways of being a species (species modes) as traits of clades. By extension from biospecies to the other concepts intended to capture the natural realities of what keeps taxa distinct, we can treat other modes as traits also, and so come to understand that theplurality of species concepts reflects the biological realities of monophyletic groups.We should expect that specialists in different organisms will tend to favour those concepts that best represent the intrinsic mechanisms that keep taxa distinct in their clades. I will address the question whether modes ofreproduction such as asexual and sexual reproduction are natural classes, given that they are paraphyletic in most clades.

Speciation is an aspect of evolutionary biology that has received little philosophical attention apart from articles mainly by biologists such as Mayr (1988). The role of speciation as a terminus a quo for the individuality of species or in the context of punctuated equilibrium theory has been discussed, but not the nature of speciation events themselves. It is the task of this paper to attempt to bring speciation events into some kind of general scheme, based primarily upon the work of Sergey Gavrilets on adaptive landscapes, using migration rate, or gene flow, as the primary scale, and concluding that adaptive and drift explanations are complementary rather than competing. I propose a distinction between intrinsic and extrinsic selection, and the notion of reproductive reach and argue that speciation modes should be discriminated in terms of gene flow, the nature of selection maintaining reproductive reach, and whether the predominant cause is selective or stochastic. I also suggest that the notion of an adaptive “quasispecies” for asexual species is the primitive notion of species, and that members of reproductively coherent sexual species are additionally coadapted to their mating partners.

In 1988, David Hull presented an evolutionary account of science. This was a direct analogy to evolutionary accounts of biological adaptation, and part of a generalized view of Darwinian selection accounts that he based upon the Universal Darwinism of Richard Dawkins. Criticisms of this view were made by, among others, Kim Sterelny, which led to it gaining only limited acceptance. Some of these criticisms are, I will argue, no longer valid in the light of developments in the formal modeling of evolution, in particular that of Sergey Gavrilets’ work on adaptive landscapes. If we can usefully recast the Hullian view of science as being driven by selection in terms of Gavrilets’ and Kaufmann’s view of there being “giant components” of high-fitness networks through any realistic adaptive landscape, we may now find it useful to ask what the adaptive pressures on science are, and to extend the metaphor into a full analogy. This is in effect to reconcile the Fisherianism of the Dawkins–Hull approach to selection and replicators, with a Wrightean drift account of social constructionist views of science, preserving, it is to be hoped, the valuable aspects of both.

David Hull's (1988c) model of science as a selection process suffers from a two-fold inability: (a) to ascertain when a lineage of theories has been established; i.e., when theories are descendants of older theories or are novelties, and what counts as a distinct lineage; and (b) to specify what the scientific analogue is of genotype and phenotype. This paper seeks to clarify these issues and to propose an abstract model of theories analogous to particulate genetic structure, in order to reconstruct relationships of descent and identity.

Pierre Trémaux’s 1865 ideas on speciation have been unjustly derided following his acceptance by Marx and rejection by Engels, and almost nobody has read his ideas in a charitable light. Here we offer an interpretation based on translating the term sol as “habitat”, in order to show that Trémaux proposed a theory of allopatric speciation before Wagner and a punctuated equilibrium theory before Gould and Eldredge, and translate the relevant discussion from the French. We believe he may have influenced Darwin’s revision to the third edition of the Origin on rates of evolution, and suggest that Gould’s dismissal of Trémaux is motivated by concern that others might think punctuated equilibrium theory was tainted by a connection with Trémaux.

Intelligent design theorist William Dembski hasproposed an ``explanatory filter'' fordistinguishing between events due to chance,lawful regularity or design. We show that ifDembski's filter were adopted as a scientificheuristic, some classical developments inscience would not be rational, and thatDembski's assertion that the filter reliablyidentifies rarefied design requires ignoringthe state of background knowledge. Ifbackground information changes even slightly,the filter's conclusion will vary wildly.Dembski fails to overcome Hume's objections toarguments from design.

Species concepts for bacteria and other microbes are contentious, because they are often asexual. There is a Problem of Homogeneity: every mutation in an asexual lineage forms a new strain, of which all descendents are clones until a new mutation occurs. We should expect that asexual organisms would form a smear or continuum. What causes the internal homogeneity of asexual lineages, if they are in fact homogeneous? Is there a natural “species concept” for “microbes”? Two main concepts devised for metazoans and metaphytes have been applied to bacteria. One is the Recombination Concept, a revised form of the Biological Species Concept in which the homogenizing mechanism is the sharing of genome fragments, somewhat akin to sexual recombination. The other is the Ecological Species Concept, in which the ecological niche is that which maintains lineages as cohesive. In this paper I will discuss these two concepts, and offer an underlying model that conjoins them, and consider the implications for species concepts in general. In short, my argument is that asexual species are instances of the most primitive and underived notion of species, which I will call “quasispecies”, following Eigen, and that sexual species are merely one derived kind of species. Moreover, I will argue that there is a continuum of recombination from simple viral models in which each strain is a clone, through to obligate recombination of 50% of the parents’ genome, and that consequently there is no sharp division between “microbial” and more familiar species.

The Nature of Classification discusses an old and generally ignored issue in the philosophy of science: natural classification. It argues for classification to be a sometimes theory-free activity in science, and discusses the existence of scientific domains, theory-dependence of observation, the inferential relations of classification and theory, and the nature of the classificatory activity in general. It focuses on biological classification, but extends the discussion to physics, psychiatry, meteorology and other special sciences.