Ingo Brigandt

Even within biology, different types of explanation can be found: causal explanations, mechanistic explanations, reductive explanations, mathematical model-based explanations, actual-sequence explanations, and robust-process explanations. On top of this, different types of explanation can be sought for the same phenomenon, entailing different conditions of what counts as a satisfactory explanation of this phenomenon. I make sense of this complexity by using the notions of explanatory aims and standards of explanatory adequacy. Pertaining to scientific practice rather than the empirical content of science, these ideas likewise matter to science education and classroom practice. Standards of explanatory adequacy permit adjudicating the goodness of different explanations suggested by students, and they underlie the explanatory sense-making one obtains upon having constructed an explanation. Explanatory aims guide the type of explanation sought after, so as to foster student engagement and motivate explanation construction.

Reductionism in the Philosophy of Science develops a novel account of reduction in science and applies it to the relationship between classical and molecular genetics. However, rather than addressing the epistemological issues that have been essential to the reductionism debate in philosophy of biology, the discussion primarily pursues ontological questions, as they are known, about reducing the mental to the physical. For Sachse construes reductionism as a purely philosophical endeavor and defends the possibility of reduction in principle, which may not be relevant to understanding reductionist reasoning and explanation occurring in scientific practice, as discussed by philosophers of science. Likewise, the conceptual framework used stems more from metaphysics and philosophy of mind than philosophy of science. Sachse's aim is twofold. First, he argues for the special sciences' being reducible to physics, by deriving the in principle possibility of epistemological reduction from ontological reduction. Second, he attempts to simultaneously make room for the legitimacy of the special sciences, effecting a conservative reduction rather than an elimination of the special sciences.

We humans are diverse. But how to understand human diversity in the case of cognitive diversity? This Element discusses how to properly investigate human behavioural and cognitive diversity, how to scientifically represent, and how to explain cognitive diversity. Since there are various methodological approaches and explanatory agendas across the cognitive and behavioural sciences, which can be more or less useful for understanding human diversity, a critical analysis is needed. And as the controversial study of sex and gender differences in cognition illustrates, the scientific representations and explanations put forward matter to society and impact public policy, including policies on mental health. But how to square the vision of human cognitive diversity with the assumption that we all share one human nature? Is cognitive diversity something to be positively valued? The author engages with these questions in connection with the issues of neurodiversity, cognitive disability, and essentialist construals of human nature.

According to many biologists, explaining the evolution of morphological novelty and behavioral innovation are central endeavors in contemporary evolutionary biology. These endeavors are inherently multidisciplinary but also have involved a high degree of controversy. One key source of controversy is the definitional diversity associated with the concept of evolutionary novelty, which can lead to contradictory claims (a novel trait according to one definition is not a novel trait according to another). We argue that this diversity should be interpreted in light of a different epistemic role played by the concept of evolutionary novelty—the structuring of a problem space or setting of an explanatory agenda—rather than the concept’s capacity to categorize traits as novel. This distinctive role is consistent with the definitional diversity and shows that the concept of novelty benefits ongoing investigation by focusing attention on answering different questions related to comprehending the origins of novelty. A review of recent theoretical and empirical work on evolutionary novelty confirms this interpretation.

Ein naturalistisches Menschenbild sieht uns Menschen und unsere geistigen Fähigkeiten als materielle Phänomene und durch Evolution entstanden. Dies ist immer wieder der Anlass zu Menschenbildkonflikten, insbesondere mit religiös fundierten Menschenbildern. Aber auch innerhalb der Verhaltens- und Kognitionswissenschaft kann man suspekte Menschenbilder finden, die kulturell bedingte Verhaltensmuster und soziale Organisationsformen als biologisch-genetisch bestimmt sehen. Zum Beispiel kann die heutige evolutionäre Psychologie behaupten, dass aufgrund unterschiedlicher sozialer Rollen während der Evolution Männer und Frauen unterschiedliche verhaltenspsychologische Tendenzen und unterschiedliche kognitive Fähigkeiten haben. Dahingegen würde ein naturwissenschaftlich und evolutionsbiologisch haltbares Menschenbild die gesamte Bandbreite menschlicher Vielfalt und kognitiver Diversität betonen.

In the 1970s, the position that species are natural kinds characterized by essences came to be challenged, and was replaced by the view that species are individuals. To date, this remains the dominant position, at least among biologists, despite influential arguments that species can be construed as homeostatic property cluster kinds (employing a revised notion of essence). Recent philosophical discussions have broadened the scope by articulating a neo-Aristotelian essentialism for species, developing a post-essentialist account of human nature, and scrutinizing temporal persistence conditions for species in the light of species de-extinction efforts. Yet most such current discussions concerning species have not relied on the notion of an essence, which also parallels recent accounts of natural kinds in the philosophy of science.

Reductionism encompasses a set of ontological, epistemological, and methodological claims about the relation of different scientific domains. The basic question of reduction is whether the properties, concepts, explanations, or methods from one scientific domain (typically at higher levels of organization) can be deduced from or explained by the properties, concepts, explanations, or methods from another domain of science (typically one about lower levels of organization). Reduction is germane to a variety of issues in philosophy of science, including the structure of scientific theories, the relations between different scientific disciplines, the nature of explanation, the diversity of methodology, and the very idea of theoretical progress, as well as to numerous topics in metaphysics and philosophy of mind, such as emergence, mereology, and supervenience.

The term ‘homology’ is persistently polysemous, defying the expectation that extensive scientific research should yield semantic stability. A common response has been to seek a unification of various prominent definitions. This paper proposes an alternative strategy, based on the insight that scientific concepts function as tools for research: When analyzing various conceptualizations of homology, we should preserve those distinguishing features that support particular research goals. We illustrate the fruitfulness of our strategy by application to two cases. First, we revisit E. Ray Lankester’s celebrated (1870) evolutionary reappraisal of homology and argue that his analysis has been distorted by assimilation to modern agendas. His ‘homogeny’ does not mean the same thing as modern evolutionary ‘homology,’ and his ‘homoplasy’ is no mere antonym. Instead, Lankester uses both new terms to pose a question that remains strikingly relevant—how do mechanistic and historical causes of morphological resemblance interact? Second, we examine the puzzle of avian digit homology, which exemplifies disciplinary differences in homology conceptualization and assessment. Recent progress has been fueled by the development of new tools within the relevant disciplines (paleontology and developmental biology) and especially by increasing interdisciplinary cooperation. Conceptual unification has played very little role in this work, which instead seeks concrete evolutionary scenarios that integrate all the available evidence. Together these cases indicate the complex relationship between concepts and other tools in homology research.

Throughout his life, John Tyler Bonner contributed to major transformations in the fields of developmental and evolutionary biology. He pondered the evolution of complexity and the significance of randomness in evolution, and was instrumental in the formation of evolutionary developmental biology. His contributions were vast, ranging from highly technical scientific articles to numerous books written for a broad audience. This historical vignette gathers reflections by several prominent researchers on the greatness of John Bonner and the implications of his work.

Accounting for the evolutionary origins of morphological novelty is one of the core challenges of contemporary evolutionary biology. A successful explanatory framework requires the integration of different biological disciplines, but the relationships between developmental biology and standard evolutionary biology remain contested. There is also disagreement about how to define the concept of evolutionary novelty. These issues were the subjects of a workshop held in November 2009 at the University of Alberta. We report on the discussion and results of this workshop, addressing questions about (i) how to define evolutionary novelty and understand its significance, (ii) how to interpret evolutionary developmental biology as a synthesis and its relation to neo-Darwinian evolutionary theory, and (iii) how to integrate disparate biological approaches in general.

Although natural philosophers have long been interested in individuality, it has been of interest to contemporary philosophers of biology because of its role in different aspects of evolutionary biology. These debates include whether species are individuals or classes, what counts as a unit of selection, and how transitions in individuality occur evolutionarily. Philosophical analyses are often conducted in terms of metaphysics (“what is an individual?”), rather than epistemology (“how can and do researchers conceptualize individuals so as to address some of their scientific goals?”). We review several philosophical distinctions in order to shift attention from metaphysics to epistemology. Many controversies involve epistemological differences rather than metaphysical disagreement. This implies that a pluralist stance about individuality in biology is warranted and has metaphysical consequences because the pluralism emerges from the diversity of scientific interests that investigate the complexity of living phenomena.

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.