A number of biologists and philosophers have noted the diversity of interpretations of evolvability in contemporary evolutionary research. Different clusters of research defined by co-citation patterns or shared methodological orientation sometimes concentrate on distinct conceptions of evolvability. We examine five different activities where the notion of evolvability plays conceptual roles in evolutionary biological investigation: setting a research agenda, characterization, explanation, prediction, and control. Our analysis of representative examples demonstrates how different conceptual roles of evolvability are quasi-independent and yet exhibit important (...) relationships across scientific activities. It also provides us with the resources to detail two distinct strategies for how evolvability can help to synthesize disparate areas of research and thereby potentially serve as a unifying concept in evolutionary biology. (shrink)

The first clear and precise statement of the axioms of qualitative probability was given by de Finetti ([1], Section 13). A more detailed treatment, based however on more complex axioms for conditional qualitative probability, was given later by Koopman [5]. De Finetti and Koopman derived a probability measure from a qualitative probability under the assumption that, for any integer n, there are n mutually exclusive, equally probable events. L. J. Savage [6] has shown that this strong assumption is unnecessary. More (...) precisely, he proves that if a qualitative probability is only fine and tight, then there is one and only one probability measure compatible with it. No property equivalent to countable additivity has been used as yet in the development of qualitative probability theory. However, since the concept of countable additivity is of such fundamental importance in measure theory, it is to be expected that an equivalent property would be of interest in qualitative probability theory, and that in particular it would simplify the proof of the existence of compatible probability measures. Such a property is introduced in this paper, under the name of monotone continuity. It is shown that, if a qualitative probability is atomless and monotonely continuous, then there is one and only one probability measure compatible with it, and this probability measure is countably additive. It is also proved that any fine and tight qualitative probability can be extended to a monotonely continuous qualitative probability, and therefore, contrary to what might be expected, there is no loss in generality if we consider only qualitative probabilities which are monotonely continuous. At the present time there is still a controversy over the interpretation which should be given to the word probability in the scientific and technical literature. Although the present writer subscribes to the opinion that this interpretation may be different in different contexts, in this paper we do not enter into this controversy. We simply remark that a qualitative probability, as a numerical one, may be interpreted either as an objective or as a subjective probability, and therefore the following axiomatic theory is compatible with both interpretations of probability. (shrink)

While the notion of chance has been central in discussions over the probabilistic nature of natural selection and genetic drift, its role in the production of variants on which populational sampling takes place has received much less philosophical attention. This article discusses the concept of chance in evolution in the light of contemporary work in evo-devo. We distinguish different levels at which randomness and chance can be defined in this context, and argue that recent research on variability and evolvability demands (...) a causal understanding of variational probabilities under which development acquires a creative, rather than a constraining role in evolution. We then provide a propensity interpretation of variational probabilities that solves a conceptual confusion between causal properties, variational probabilities and extant variation present in the literature, and explore some metaphysical consequences that follow from our interpretation, specifically with regards to the nature of developmental types. 2.1Mutational randomness 2.2Morphological randomness 2.3Adaptive randomness3Variability and Phenotypic Probabilities 3.1The RNA model as a model for evo-devo4Evolvability and the Probability of Evolving5Variational Propensities in Evo-Devo 5.1Individuating variational propensities 5.2Developmental types6Conclusion. (shrink)

The developmental properties of organisms play important roles in the generation of variation necessary for evolutionary change. But how can individual development steer the course of evolution? To answer this question, we introduce developmental channeling as a disposition of individual organisms that shapes their possible developmental trajectories and evolutionary dappling as an evolutionary outcome in which the space of possible organismic forms is dappled—it is only partially filled. We then trace out the implications of the channeling-dappling framework for contemporary debates (...) in the philosophy of evolution, including evolvability, reciprocal causation, and the extended evolutionary synthesis. (shrink)

A disposition or dispositional property is a capacity, ability, or potential to display or exhibit some outcome. Evolvability refers to a disposition to evolve. This chapter discusses why the dispositional nature of evolvability matters—why philosophical distinctions about dispositions can have scientific implications. To that end, we build a conceptual toolkit with vocabulary from prior philosophical analyses using a different disposition: protein foldability. We then apply this toolkit to address several methodological questions related to evolvability. What entities are the bearers of (...) evolvability? What features causally contribute to the disposition of evolvability? How does evolvability manifest? The various possible answers to these questions available from philosophical distinctions suggest key implications for why the concept of evolvability as a disposition is useful in evolutionary research. These include (1) securing scientific virtues (e.g., explanatory depth and generalization, prediction or retrodiction, and control or manipulation) and (2) fostering interdisciplinary collaboration through the coordination of definitional diversity and different types of inquiry. Together these facilitate concentration on a variety of research questions at different levels of organization and on distinct time scales, all of which should be expected for a complex dispositional property such as evolvability. (shrink)

Evolutionary developmental biology (evo-devo) is often vindicated by theoreticians of the field as a mechanistic science that brings a mechanistic perspective into evolutionary biology. Usually, it is also portrayed as stressing the causal role that development plays in the evolutionary process. However, mechanistic studies in evo-devo typically refer to lineage-specific transformations and lack the generality that evolutionary explanations usually aim for. After reviewing the prospects and limits of a mechanistic view of evo-devo and their studies of homology and novelty, in (...) this chapter I propose a way to combine the mechanistic view of evo-devo with the population-level inclination of more classical approaches to evolution. Such a proposal provides a philosophical framework for understanding the causal role of development in evolution both as mechanistic and as generalizable, population-level. (shrink)

Unlike many dominant images of thought that are centered on searching for foundations whose coherence is found in binary logics or biunivocal relations, Gilles Deleuze and Félix Guattari’s philosophy constitutes a way of thinking through machines that produce pure multiplicities by virtue of intensive differences. What is important with regards to machines is to refrain from any attempt at defining or understanding them—they cannot be delimited and are a-signifying—and to try to make them work, such that various flows of thought (...) may circulate through them, intermingling with and interrupting each other. Even though any machine groups together many heterogeneous elements, literary machines are interesting insofar as they can reach a level of the fragmentary whereby the determinant potency of intensive differences can be expressed. This article experiments with Maurice Blanchot’s literary machine—especially with his idea of the neuter—to discover operations that could help to dismantle the foundations of dominant images of thought. (shrink)