Measuring evolutionary independence: A pragmatic approach to species classification Abstract After decades of debates about species concepts, there is broad agreement that species are evolving lineages. However, species classification is still in a state of disorder: different methods of delimitation lead to competing outcomes for the same organisms, and the groups recognised as species are of widely different kinds. This paper considers whether this problem can be resolved by developing a unitary scale for evolutionary independence. Such a scale would show clearly when groups are comparable and allow taxonomists to choose a conventional threshold of independence for species status. Existing measurement approaches to species delimitation are typically shot down by what I call the heterogeneity objection, according to which independently evolving groups are too heterogeneous to be captured by a single scale. I draw a parallel with the measurement of temperature to argue that this objection does not provide sufficient reasons to abandon the measurement approach, and that such an approach may even help to make the vague notion of evolutionary independence more precise.

On mycorrhizal individuality Abstract This paper argues that a plant together with the symbiotic fungus attached to its roots, a mycorrhizal collective, is an evolutionary individual, and further, that mycorrhizal individuality has important implications for evolutionary theory. Theoretical individuation is defended and then employed to show that mycorrhizal collectives function as interactors according to David Hull’s replicator–interactor model of evolution by natural selection, and because they have the potential to engage in pseudo-vertical transmission, mycorrhizal collectives also function as Darwinian individuals, according to Peter Godfrey-Smith’s Darwinian Populations model of evolution by natural selection. Mycorrhizae in nature usually connect the roots of multiple plants, so mycorrhizal individuality entails the existence of overlapping evolutionary individuals, and because the potential to engage in pseudo-vertical transmission comes in degrees, it follows that these overlapping evolutionary individuals also come in degrees. I suggest here that the degree of evolutionary individuality in a symbiotic collective corresponds to its probability of reproducing with vertical or pseudo-vertical transmission. This probability constitutes a fourth parameter of graded Darwinian individuality in collective reproducers and warrants an update to Godfrey-Smith’s 3D model.

Regression explanation and statistical autonomy Abstract The phenomenon of regression toward the mean is notoriously liable to be overlooked or misunderstood; regression fallacies are easy to commit. But even when regression phenomena are duly recognized, it remains perplexing how they can feature in explanations. This article develops a philosophical account of regression explanations as “statistically autonomous” explanations that cannot be deepened by adducing details about causal histories, even if the explananda as such are embedded in the causal structure of the world. That regression explanations have statistical autonomy was first suggested by Ian Hacking and has recently been defended and elaborated by André Ariew, Yasha Rohwer, and Collin Rice. However, I will argue that these analyses fail to capture what regression’s statistical autonomy consists in and how it sets regression explanations apart from other kinds of explanation. The alternative account I develop also shows what is amiss with a recent denial of regression’s statistical autonomy. Marc Lange has argued that facts that can be explained as regression phenomena can in principle also be explained by citing a conjunction of causal histories. The account of regression explanation developed here shows that his argument is based on a misunderstanding of the nature of statistical autonomy.

Further clarification on permissive and instructive causes Abstract I respond to recent criticism of my analysis of the permissive-instructive distinction and outline problems with the alternative analysis on offer. Amongst other problems, I argue that the use of formal measures is unclear and unmotivated, that the distinction is conflated with others that are not equivalent, and that no good reasons are provided for thinking the alternative model or formal measure tracks what biologists are interested in. I also clarify my own analysis where it has been misunderstood or ignored.

Logical fallacies and reasonable debates in invasion biology: a response to Guiaşu and Tindale Abstract This critical note responds to Guiaşu and Tindale’s “Logical fallacies and invasion biology,” from our perspective as ecologists and philosophers of science engaged in debates about invasion biology and invasive species. We agree that “the level of charges and dismissals” surrounding these debates might be “unhealthy” and that “it will be very difficult for dialogues to move forward unless genuine attempts are made to understand the positions being held and to clarify the terms involved.” Although they raise several important scientific, conceptual, and ethical issues at the foundations of invasion biology, we believe Guiaşu and Tindale’s attempts to clarify the debate were unsuccessful. Like some other critics of the field, they tend to misrepresent invasion biology by cherry-picking and constructing “straw people,” inaccurately portraying invasion biology, and thus failing to elevate the dialogue. In this critique, we clarify areas in the invasion biology literature misrepresented by Guiaşu and Tindale. We attempt to provide a more balanced view of areas of reasonable debate within invasion biology, including disputes about empirical evidence, diverse risk attitudes, and other diverse ethical commitments.

Graphical causal models of social adaptation and Hamilton’s rule Abstract Part of Allen et al.’s criticism of Hamilton’s rule makes sense only if we are interested in social adaptation rather than merely social selection. Under the assumption that we are interested in casually modeling social adaptation, I illustrate how graphical causal models of social adaptation can be useful for predicting evolution by adaptation. I then argue for two consequences of this approach given some of the recent philosophical literature. I argue Birch’s claim that the proper way to understand Hamilton’s rule is as providing an organizational framework for causal models is incorrect. I provide an account of a causally adequate decomposition of evolutionary change due to social adaptation and show that my account is superior to Okasha’s.

The evolution of languages of thought Abstract The idea that cognition makes use of one or more “languages of thought” remains central to much cognitive-scientific and philosophical theorizing. And yet, virtually no attention has been paid to the question of how a language of thought might evolve in the first place. In this article, I take some steps towards addressing this issue. With the aid of the so-called Sender–Receiver framework, I elucidate a family of distinctions and processes which enable us to see how languages of thought might evolve via a series of small, incremental changes. While much work doubtlessly remains to be done in this area, I hope to at least show that there need be nothing mysterious about the existence of languages of thought on evolutionary grounds.

Gould’s laws: a second perspective Abstract In a recent paper, Chris Haufe paints a provocative portrait of the late paleontologist Stephen Jay Gould. His principal aim is to resolve a “paradox” arising from a prima facie inconsistent pair of commitments: (a) Gould believed that the biological facts could have been otherwise (the Replay Thesis), and (b) Gould believed that there are evolutionary laws. In order to resolve this paradox, Haufe makes two substantive claims: (1) Gould was aware of the challenges that the Replay Thesis posed for a law-centered science of evolution, even early in his career, and (2) Gould endeavored to meet these challenges by deploying the “species-as-particles approach.” In this paper, I put pressure on both of these claims. By examining the goals and methods of Gould’s first “nomothetic research program,” the science of form, I show that it does not fit the picture of nomothetic science that Haufe illustrates. Additionally, I show that no straightforward connection exists between Gould’s understanding of contingency and his (short-lived) adoption of the species-as-particles approach. I propose that Gould’s career can be usefully split into three periods, each of which employed a distinct strategy for establishing distinctively paleontological contributions to evolutionary theory.

Are emotional states based in the brain? A critique of affective brainocentrism from a physiological perspective Abstract We call affective brainocentrism the tendency to privilege the brain over other parts of the organism when defining or explaining emotions. We distinguish two versions of this tendency. According to brain-sufficient, emotional states are entirely realized by brain processes. According to brain-master, emotional states are realized by both brain and bodily processes, but the latter are entirely driven by the brain: the brain is the master regulator of bodily processes. We argue that both these claims are problematic, and we draw on physiological accounts of stress to make our main case. These accounts illustrate the existence of complex interactions between the brain and endocrine systems, the immune system, the enteric nervous system, and even gut microbiota. We argue that, because of these complex brain–body interactions, the brain cannot be isolated and identified as the basis of stress. We also mention recent evidence suggesting that complex brain–body interactions characterize the physiology of depression and anxiety. Finally, we call for an alternative dynamical, systemic, and embodied approach to the study of the physiology of emotions that does not privilege the brain, but rather aims at understanding how mutually regulating brain and bodily processes jointly realize a variety of emotional states.

Psychoneural reduction: a perspective from neural circuits Abstract Psychoneural reduction has been debated extensively in the philosophy of neuroscience. In this article I will evaluate metascientific approaches that claim direct molecular and cellular explanations of cognitive functions. I will initially consider the issues involved in linking cellular properties to behaviour from the general perspective of neural circuits. These circuits that integrate the molecular and cellular components underlying cognition and behaviour, making consideration of circuit properties relevant to reductionist debates. I will then apply this general perspective to specific systems where psychoneural reduction has been claimed, namely hippocampal long-term potentiation and the Aplysia gill-withdrawal reflex.