Philippe Huneman

Philosophers of science have recently focused on the scientific activity of modeling phenomena, and explicated several of its properties, as well as the activities embedded into it. A first approach to modeling has been elaborated in terms of representing a target system: yet other epistemic functions, such as producing data or detecting phenomena, are at least as relevant. Additional useful distinctions have emerged, such as the one between phenomenological and mechanistic models. In biological sciences, besides mathematical models, models now come in three forms: in vivo, in vitro and in silico. Each has been investigated separately, and many specific problems they raised have been laid out. Another relevant distinction is disciplinary: do models differ in significant ways according to the discipline involved—medicine or biology, evolutionary biology or earth science? Focusing on either this threefold distinction or the disciplinary boundaries reveals that they might not be sufficient from a philosophical perspective. On the contrary, focusing on the interaction between these various kinds of models, some interesting forms of explanation come to the fore, as is exemplified by the papers included in this issue. On the other hand, a focus on the use of models, rather than on their content, shows that the distinction between biological and medical models is theoretically sound.

Natural selection is often envisaged as the ultimate cause of the apparent rationality exhibited by organisms in their specific habitat. Given the equivalence between selection and rationality as maximizing processes, one would indeed expect organisms to implement rational decision-makers. Yet, many violations of the clauses of rationality have been witnessed in various species such as starlings, hummingbirds, amoebas and honeybees. This paper attempts to interpret such discrepancies between economic rationality and biological rationality. After having distinguished two kinds of rationality we introduce irrationality as a negation of economic rationality by biologically rational decision-makers. Focusing mainly on those instances of irrationalities that can be understood as exhibiting inconsistency in making choices, i.e. as non-conformity of a given behaviour to axioms such as transitivity or independence of irrelevant alternatives, we propose two possible families of Darwinian explanations that may account for these apparent irrationalities. First, we consider cases where natural selection may have been an indirect cause of irrationality. Second, we consider putative cases where violations of rationality axioms may have been directly favored by natural selection. Though the latter cases seem to clearly contradict our intuitive representation of natural selection as a process that maximizes fitness, we argue that they are actually unproblematic; for often, they can be redescribed as cases where no rationality axiom is violated, or as situations where no adaptive solution exists in the first place.

This paper uses formal Darwinism as elaborated by Alan Grafen to articulate an explanatory pluralism that casts light upon two strands of controversies running across evolutionary biology, viz., the place of organisms versus genes, and the role of adaptation. Formal Darwinism shows that natural selection can be viewed either physics-style, as a dynamics of alleles, or in the style of economics as an optimizing process. After presenting such pluralism, I argue first that whereas population genetics does not support optimization, optimality can still be taken as a default hypothesis when modeling evolutionary processes; and second, that organisms have an explanatory role in evolutionary theory, since they are involved in the economic perspective of optimization. Finally, in order to ask whether the Modern Synthesis can indeed provide a theory of organisms, I apply a Kantian-inspired theoretical view of organisms (underlying much developmental modeling), according to which they are both designed entities and subjects of intrinsic circular processes involving the whole organism and its parts. I first show that the design aspect is accountable for in terms of the Modern Synthesis understood in the formal Darwinism framework. I then question whether the latter aspect of organisms can also be ultimately captured in the same framework, and to this purpose devise an empirical test relying on an assessment of the relative weight of genetic elements in developmental and functional gene regulatory networks.

This paper interprets the two pages devoted in the Critique of Pure Reason to a critique of Leibniz’s view of organisms as infinitely organized machines. It argues that this issue of organisms represents a crucial test-case for Kant in regard to the conflicting notions of space, continuity and divisibility held by classical metaphysics and by criticism. I first present Leibniz’s doctrine and its justification. In a second step, I explain the general reasoning by which Kant defines the problem of the Antinomies, and then I specify the case of the Second Antinomy. Then, I ask why the organism raises specific issues for Kant’s solution of the Second Antinomy, and why it sheds light on the nature of Leibniz’s metaphysical assumptions about organisms. The last section considers this critique of Leibniz from the perspective of Kant’s future theory of organisms in the third Critique, specifying its role in the development of a Kantian view of organisms with regard to the changes occurring at the same time in the life sciences.

I investigate the relationship between adaptation, as defined in evolutionary theory through natural selection, and the concept of emergence. I argue that there is an essential correlation between the former, and “emergence” defined in the field of algorithmic simulations. I first show that the computational concept of emergence (in terms of incompressible simulation) can be correlated with a causal criterion of emergence (in terms of the specificity of the explanation of global patterns). On this ground, I argue that emergence in general involves some sort of selective processes. Finally, I show that a second criterion, concerning novel explanatory regularities following the emergence of a pattern, captures the robustness of emergence displayed by some cases of emergence (according to the first criterion). Emergent processes fulfilling both criteria are therefore exemplified in evolutionary biology by some so-called “innovations”, and mostly by the new units of fitness or new kinds of adaptations (like sexual reproduction, multicellular organisms, cells, societies) sometimes called “major transitions in evolution”, that recent research programs (Maynard-Smith and Szathmary 1995 ; Michod 1999 ) aims at explaining.

This paper argues that besides mechanistic explanations, there is a kind of explanation that relies upon “topological” properties of systems in order to derive the explanandum as a consequence, and which does not consider mechanisms or causal processes. I first investigate topological explanations in the case of ecological research on the stability of ecosystems. Then I contrast them with mechanistic explanations, thereby distinguishing the kind of realization they involve from the realization relations entailed by mechanistic explanations, and explain how both kinds of explanations may be articulated in practice. The second section, expanding on the case of ecological stability, considers the phenomenon of robustness at all levels of the biological hierarchy in order to show that topological explanations are indeed pervasive there. Reasons are suggested for this, in which “neutral network” explanations are singled out as a form of topological explanation that spans across many levels. Finally, I appeal to the distinction of explanatory regimes to cast light on a controversy in philosophy of biology, the issue of contingence in evolution, which is shown to essentially involve issues about realization

This paper investigates the conception of causation required in order to make sense of natural selection as a causal explanation of changes in traits or allele frequencies. It claims that under a counterfactual account of causation, natural selection is constituted by the causal relevance of traits and alleles to the variation in traits and alleles frequencies. The “statisticalist” view of selection (Walsh, Matthen, Ariew, Lewens) has shown that natural selection is not a cause superadded to the causal interactions between individual organisms. It also claimed that the only causation at work is those aggregated individual interactions, natural selection being only predictive and explanatory, but it is implicitly committed to a process-view of causation. I formulate a counterfactual construal of the causal statements underlying selectionist explanations, and show that they hold because of the reference they make to ecological reliable factors. Considering case studies, I argue that this counterfactual view of causal relevance proper to natural selection captures more salient features of evolutionary explanations than the statisticalist view, and especially makes sense of the difference between selection and drift. I eventually establish equivalence between causal relevance of traits and natural selection itself as a cause

‘Statisticalists’ argue that the individual interactions of organisms taken together constitute natural selection. On this view, natural selection is an aggregated effect of interactions rather than some added cause acting on populations. The statisticalists’ view entails that natural selection and drift are indistinguishable aggregated effects of interactions, so that it becomes impossible to make a difference between them. The present paper attempts to make sense of the difference between selection and drift, given the main insights of statisticalism; basically, it will disentangle the various kinds of indistinguishability between selection and drift that happen within biology, by examining the epistemological and metaphysical nature of the distinction between selection and drift. It will be based on a ‘difference-making account’ of selection. The first section will explicate the inscrutability of selection and drift, its various types in the statisticalist writings, and its implications. The second section specifies concepts of natural selection and drift in the difference making account of selection I am using, and shows that one can derive from this the statistical signatures of selection and drift. On this basis I focus on one sort of indistinguishability issue about selection and drift, which I call epistemic opacity, and explain why it mostly affects small populations. The last section explains why epistemic opacity does not raise an genuine epistemic problem for evolutionary biology

This chapter surveys the philosophical problems raised by the two Darwinian claims of the existence of a Tree of a life, and the explanatory power of natural selection. It explores the specificity of explanations by natural selection, emphasizing the high context-dependency of any process of selection. Some consequences are drawn about the difficulty of those explanations to fit a nomological model of explanation, and the irreducibility of their historic-narrative dimension. The paper introduces to the debates about units of selection, stating the compelling force of genic selectionnism but highlighting some critiques. Then it addresses the limits of selectionist explanations : the compared status of selection, drift and phylogenetic inertia are investigated, and the debates over adaptationism are presented, with the aim of defining the varieties of adaptationisms as research programs. In order to assess the scope of natural selection, the chapter addresses weak and strong challenges to the Synthetic theory of evolution, both from paleontology (punctuated equilibria, Gould’s contingency thesis) and evolutionary theory of development. We finally sketch some consequences of evolutionary theory concerning philosophical questions about human nature, on the basis of the hypothesis of the universality of selectionist explanations: this part deals mostly with epistemology and psychology.

The problem of generation has been, for Kant scholars, a kind of test of Kant's successive concepts of finality. Although he deplores the absence of a naturalistic account of purposiveness (and hence of reproduction) in his pre-critical writings, in the First Critique he nevertheless presents a "reductionist" view of finality in the Transcendental Dialectic's Appendices. This finality can be used only as a language, extended to the whole of nature, but which must be filled with mechanistic explanations. Therefore, in 1781, mechanism and teleology are synonymous languages. Despite the differences between its two authors, the Wolffian embryology, exposed in the Theorie der Generation (1764), and debated by Blumenbach's dissertation on Bildungstrieb, enabled Kant to resolve the philosophical problem of natural generation, and subsequently to determine what is proper to the explanation of living processes. Thus, in the Third Critique he could give another account of purposiveness, restricted to the organism, and more realistic than his former one; this philosophical reappraisal of purposiveness in embryology required the new concept of "simply reflexive judgement", and the correlated notion of "regulative principle". Thus framed, this naturalized teleology provided some answers to the Kantian problem of order and contingency after the end of classical (Leibnizian) metaphysics

Recently some philosophers have emphasized a potentially irreconcilable conceptual antagonism between the statistical characterization of natural selection and the standard scientific discussion of natural selection in terms of forces and causes. Other philosophers have developed an account of the causal character of selectionist statements represented in terms of counterfactuals. I examine the compatibility between such statisticalism and counterfactually based causal accounts of natural selection by distinguishing two distinct statisticalist claims: firstly the suggested impossibility for natural selection to be a cause acting upon populations and secondly the conceptualization that all evolutionary causes occur at the level of interactions between individual organisms. I argue that deriving the latter from the former involves supplementary assumptions concerning precisely what causation is. I critically examine two of these assumptions purportedly preventing natural selection being regarded as a cause: the locality claim and the modularity claim. I conclude that justifying the strongest version of statisticalism—i.e. evolutionary causation only occurs at the level of individual interactions between organisms—would require further metaphysical arguments that are likely to be deemed highly problematic. Additionally, I argue that such a metaphysical position would be considered incongruous with both our scientific and ordinary use of the concepts of causality and explanation as employed within our everyday epistemological framework

This volume focuses on various questions concerning the interpretation of probability and probabilistic reasoning in biology and physics. It is inspired by the idea that philosophers of biology and philosophers of physics who work on the foundations of their disciplines encounter similar questions and problems concerning the role and application of probability, and that interaction between the two communities will be both interesting and fruitful. In this introduction we present the background to the main questions that the volume focuses on and summarize the highlights of the individual contributions.

This paper argues that in some explanations mathematics are playing an explanatory rather than a representational role, and that this feature unifies many types of non-causal or non-mechanistic explanations that some philosophers of science have been recently exploring under various names. After showing how mathematics can play either a representational or an explanatory role by considering two alternative explanations of a same biological pattern—“Bergmann’s rule”—I offer an example of an explanation where the bulk of the explanatory job is done by a mathematical theorem, and where mechanisms involved in the target systems are not explanatorily relevant. Then I account for the way mathematical properties may function in an explanatory way within an explanation by arguing that some mathematical propositions involving variables non directly referring to the target system features constitute constraints to which a whole class of systems should comply, provided they are describable by a mathematical object concerned by those propositions. According to such “constraint account”, those mathematical facts are directly entailing the explanandum, as a consequence of such constraints. I call those explanations “structural”, because here properties of mathematical structures are accounting for the explanandum; various kinds of mathematical structures thereby define various types of structural explanations.

This paper uses the framework of Formal Darwinism (FD) to evaluate organism-centric critiques of the Modern Synthesis (MS). The first section argues that the FD project reconciles two kinds of selective explanations in biology. Thus it is not correct to say that the MS neglects organisms—instead, it explains organisms’ design, as argued in the second section. In the third section I employ a concept of the organism derived from Kant that has two aspects: the parts presupposing the whole, and the productivity of the parts in relation to the whole. The first aspect corresponds to the “design” that FD explains, whereas the second aspect is something about which the MS is largely silent

The neutral theory of biodiversity assumes that coexisting organisms are equally able to survive, reproduce and disperse, but predicts that stochastic fluctuations of these abilities drive diversity dynamics. It predicts remarkably well many biodiversity patterns, although substantial evidence for the role of niche variation across organisms seems contradictory. Here, we discuss this apparent paradox by exploring the meaning and implications of ecological equivalence. We address the question whether neutral theory provides an explanation for biodiversity patterns and acknowledges causal processes. We underline that ecological equivalence, although central to neutral theory, can emerge at local and regional scales from niche-based processes through equalizing and stabilizing mechanisms. Such emerging equivalence corresponds to a weak conception of neutral theory, as opposed to the assumption of strict equivalence at individual level in the strong conception. We show that this duality is related to diverging views on hypothesis-testing and modeling in ecology. In addition, the stochastic dynamics exposed in neutral theory are pervasive in ecological systems and, rather than a null hypothesis, ecological equivalence is best understood as a parsimonious baseline to address biodiversity dynamics at multiple scales.

Among many properties distinguishing emergence, such as novelty, irreducibility and unpredictability, computational accounts of emergence in terms of computational incompressibility aim first at making sense of such unpredictability. Those accounts prove to be more objective than usual accounts in terms of levels of mereology, which often face objections of being too epistemic. The present paper defends computational accounts against some objections, and develops what such notions bring to the usual idea of unpredictability. I distinguish the objective unpredictability, compatible with determinism and entailed by emergence, and various possibilities of predictability at emergent levels. This makes sense of practices common in complex systems studies that forge qualitative predictions on the basis of comparisons of simulations with multiple values of parameters. I consider robustness analysis as a way to ensure the ontological character of computational emergence. Finally, I focus on the property of novelty, as it is displayed by biological evolution, and ask whether computer simulations of evolution can produce the same kind of emergence as the open-ended evolution attested in Phanerozoic records