Devin Henry

This chapter examines the role of optimality reasoning in Aristotle’s natural science. By the phrase ‘optimality reasoning’ Aristotle means reasoning that appeals to some conception of ‘what is best’. This is used to explain why things are the way they are. This pattern of reasoning is first introduced in the famous passage at _Phaedo_ 97b8-98a2, where (Plato’s) Socrates invokes ‘what is best’ as a cause (_aitia_) of things in nature. The chapter explores three questions that arise in connection with Aristotle’s use of the optimality principle: How do we understand the concept of ‘the best’ at work in the principle? How does Aristotle conceive of ‘the range of possibilities’? What role does optimality reasoning play in Aristotle’s natural science? Is it a special form of demonstration in which the optimality principle functions as one of its premises, or is it a heuristic device that helps uncover those causally relevant features of a natural substances that ultimately serve as middle terms in demonstrations? The final section returns to the comparison between Plato and Aristotle. It concludes that despite their general agreement, it would be a mistake to think that Aristotle simply took over Plato’s use of optimality reasoning without significant modifications.

This chapter provides an overview of Aristotle’s understanding of animal nature, drawing on his zoological treatises as well as his writings on the soul and psychological faculties. Particular focus is given to his appreciation of the complex cognitive powers of animals and of their capacity for voluntary action. Aristotle’s views on animal behavior (ethology) are also discussed. While the chapter does not question Aristotle’s notorious denial of rationality to humans, it does show that he was alive to the signs of intelligence in animals. Animal mental capacities are, indeed, analogous to those of humans.

In this paper I examine Aristotle’s biological use of the concept of analogy. On the reading I defend, biological analogues are parts that realize the same capacity of soul or occupy a similar location in the animals whose parts they are but are not specific (“more-and-less”) modifications of the same underlying material substratum. The concept of analogy serves two principal functions in Aristotle’s biology. First, Aristotle uses analogy as a tool for classifying animals into separate natural kinds (Part 3). Second, analogy plays an explanatory role in which the same causal explanation is transferred to “φ and its analogue” (Part 4). Here the function of analogy is to group different parts into a single explanatory class unified on the basis of shared causes. One of the upshots of my interpretation is that, while analogical unity may allow us to posit a common explanation for φ and its analogue, it is not grounds for treating the class of animals that ­possess those parts as a natural kind. For Aristotle, natural kinds are groups whose shared similarities must result from common causes operating on a common material substratum.

This book consolidates emerging research on Aristotle's science and ethics in order to explore the extent to which the concepts, methods, and practices he developed for scientific inquiry and explanation are used to investigate moral phenomena. Each chapter shows, in a different way, that Aristotle's ethics is much more like a science than it is typically represented. The upshot of this is twofold. First, uncovering the links between Aristotle's science and ethics promises to open up new and innovative directions for research into his moral philosophy. Second, showing why Aristotle thinks ethics can never be fully assimilated to the model of science will help shed new light on his views about the limits of science. The volume thus promises to make a significant contribution to our understanding of the epistemological, metaphysical, and psychological foundations of Aristotle's ethics

This book examines an important area of Aristotle's philosophy: the generation of substances. While other changes presuppose the existence of a substance (Socrates grows taller), substantial generation results in something genuinely new that did not exist before (Socrates himself). The central argument of this book is that Aristotle defends a 'hylomorphic' model of substantial generation. In its most complete formulation, this model says that substantial generation involves three principles: (1) matter, which is the subject from which the change proceeds; (2) form, which is the end towards which the process advances; and (3) an efficient cause, which directs the process towards that form. By examining the development of this model across Aristotle's works, Devin Henry seeks to deepen our grasp on how the doctrine of hylomorphism - understood as a blueprint for thinking about the world - informs our understanding of the process by which new substances come into being.

Aristotle on Definition is an exceptional piece of scholarship. Its arguments are carefully justified, sophisticated, and far-reaching. Those interested in Aristotle's theory of definition will find this book a nice compliment to David Charles' Meaning and Essence. Whereas Charles examines Aristotle's theory of syllogistic definitions, Deslauriers focuses mainly on the concept of immediate definitions .It is impossible to do justice to the entire book. In what follows I shall attempt to isolate one of its main lines of argument to give the reader a sense of the book's content.In chapter 2, Deslauriers draws our attention to four types of definition identified in the Posterior Analytics and sets out to explore the differences between them. She focuses on two basic kinds of definition, what she calls "syllogistic" definitions and "immediate" definitions. Syllogistic definitions are accounts that indicate what something is through a middle term and are formulated by rearranging the terms of a demonstrative syllogism, whereas immediate definitions express propositions that cannot be displayed in demonstrations. Instead, they are arrived at and displayed through division by genus and differentiae. According to Deslauriers, Aristotle's account of these two basic kinds of

The intellectual history of evolutionary theory really does not begin in earnest until the late seventeenth/early eighteenth century. Prior to that, the idea that species might have evolved over time was not a serious possibility for most naturalists and philosophers. There is certainly no substantive debate in antiquity about evolution in the modern sense. There were really only two competing explanations for how living things came to have the parts they do: design or blind chance. Ancient Greek Atomism, for example, taught that all composite bodies, including living things, are generated through the random collision of atoms as they rebel and move in the void. Plato and Aristotle both dismissed this possibility on the grounds that living things are too complex and too well-adapted to be products of chance. This eventually became the central premise in Galen’s own Argument from Design. That species forms might have gradually evolved over time by a process of natural selection was not seen as a plausible alternative. Of course, such a theory had been proposed by Empedocles in the fifth century BCE. But because his theory still relied heavily on chance, it was not taken seriously by any of the later ancient Greek or Roman thinkers. My aim in this paper is to investigate the reasons why evolutionary thinking failed to gain momentum in antiquity after its introduction by Empedocles.

In this paper I explore Aristotle’s views on natural kinds and the compatibility of pluralism and realism, a topic that has generated considerable interest among contemporary philosophers. I argue that, when it came to zoology, Aristotle denied that there is only one way of organizing the diversity of the living world into natural kinds that will yield a single, unified system of classification. Instead, living things can be grouped and regrouped into various cross-cutting kinds on the basis of objective similarities and differences in ways that subserve the explanatory context. Since the explanatory aims of zoology are diverse and variegated, the kinds it recognizes must be equally diverse and variegated. At the same time, there are certain constraints on which kinds can be selected. And those constraints derive more from the causal structure of the world than from the proclivities of the classifier (hence the realism). This distinguishes Aristotle’s version of pluralistic realism from those contemporary versions (like Dupré’s “promiscuous realism”) that treat all or most classifications of a given domain as equally legitimate and not just a sub-set of kinds recognized by the science that studies it. By contrast, Aristotle privileges scientifically important kinds on the basis of their role in causal investigations. On this picture natural kinds are those kinds with the sort of causal structure that allows them to enter into scientific explanations. In the final section I argue that Aristotle’s zoology should remain of interest to philosophers and biologists alike insofar as it combines a pluralistic form of realism with a rank-free approach to classification.

It has become somewhat of a platitude to call Aristotle the first epigenesist insofar as he thought form and structure emerged gradually from an unorganized, amorphous embryo. But modern biology now recognizes two senses of “epigenesis”. The first is this more familiar idea about the gradual emergence of form and structure, which is traditionally opposed to the idea of preformationism. But modern biologists also use “epigenesis” to emphasize the context-dependency of the process itself. Used in this sense development is not simply the unfolding of a pre-determined sequence of changes specified in advance by the organism’s genotype. It is also sensitive to inputs from the internal and external environment, which help determine in real-time which of the many potential developmental pathways are actualized during the process. Within this paradigm developing embryos are viewed as dynamic and responsive systems that react to inputs from the internal and external environment ‘on the fly’. In this paper I argue that, while Aristotle was an epigenesist in the first sense, he would have rejected epigenesis in the more modern sense. First, Aristotle’s model of choice for a developing embryo is the automaton that executes a set of preset movements (GA 734b9-13, 741b7-15). The automatons he has in mind are not dynamic AI systems capable of modifying their behaviour on the fly in response to environmental cues but completely deterministic mechanisms whose movements are fixed by their original design. Second, given Aristotle’s views about the different kinds of causal powers there are, it looks like only intentional agents endowed with actual decision-making powers could be capable of the sort of plasticity at the core of a more dynamic epigenesis. For that kind of epigenesis requires powers for alternative outcomes, and Aristotle is explicit that such powers require rational desires (προαίρεσις) that control which of those alternatives to bring about. If I am right, then he could not have made sense of the idea of a developing embryo (as a non-intentional system) making adjustments to its phenotype on the fly in response to emerging problems and opportunities, given the conceptual resources available to him.

The aim of this paper is to evaluate the level of gender bias in Aristotle’s Generation of Animals while exercising due care in the analysis of its arguments. I argue that while the GA theory is clearly sexist, the traditional interpretation fails to diagnose the problem correctly. The traditional interpretation focuses on three main sources of evidence: (1) Aristotle’s claim that the female is, as it were, a “disabled” (πεπηρωμένον) male; (2) the claim at GA IV.3, 767b6-8 that females are a departure from the kind; and (3) Aristotle’s supposed claim at GA IV.3, 768a21-8 that the most ideal outcome of reproduction is a male offspring that perfectly resembles its father. I argue that each of these passages has either been misunderstood or misrepresented by commentators. In none of these places is Aristotle suggesting that females are imperfect members of the species or that they result from the failure to achieve some teleological goal. I defend the view that the GA does not see reproduction as occurring for the sake of producing males; rather, what sex an embryo happens to become is determined entirely by non-teleological forces operating through material necessity. This interpretation is consistent with Aristotle’s view in GA II.5 that females have the same soul as the male (741a7) as well as the argument in Metaphysics X.9 that sexual difference is not part of the species form but is an affection (πάθος) arising from the matter (1058b21-4). While the traditional interpretation has tended to exaggerate the level of sexism in Aristotle’s
developmental biology, the GA is by no means free of gender bias as some recent scholarship has claimed. In the final section of the paper I point to one passage where Aristotle clearly falls back on sexist assumptions in order to answer the difficult question, “Why are animals divided into sexes?”. I argue that this passage in particular poses a serious challenge
to anyone attempting to absolve Aristotle’s developmental biology of the charge of sexism.

The focus of this paper is Aristotle's solution to the problem inherited from Socrates: How could a man fail to restrain himself when he believes that what he desires is wrong? In NE 7 Aristotle attempts to reconcile the Socratic denial of akrasia with the commonly held opinion that people act in ways they know to be bad, even when it is in their power to act otherwise. This project turns out to be largely successful, for what Aristotle shows us is that if we distinguish between two ways of having knowledge (potentially and actually), the Socratic thesis can effectively account for a wide range of cases (collectively referred to here as drunk-akrasia) in which an agent acts contrary to his general knowledge of the Good, yet can still be said to know in the qualified sense that his actions are wrong. However, Book 7 also shows that the Socratic account of akrasia cannot take us any farther than drunk-akrasia, for unlike drunk-akrasia, genuine akrasia cannot be reduced to a failure of knowledge. This agent knows in the unqualified sense that his actions are wrong. The starting-point of my argument is that Aristotle's explanation of genuine akrasia requires a different solution than the one found in NE 7 which relies on the distinction between qualified and unqualified knowing: genuinely akratic behaviour is due to the absence of an internal conflict that a desire for the proper pleasures of temperance would create if he could experience them.

This paper focuses on two methodological questions that arise from Plato’s account of collection and division. First, what place does the method of collection and division occupy in Plato’s account of philosophical inquiry? Second, do collection and division in fact constitute a formal “method” (as most scholars assume) or are they simply informal techniques that the philosopher has in her toolkit for accomplishing different philosophical tasks? I argue that Plato sees collection and division as useful tools for achieving two distinct goals – generating real definitions and discovering the basic natural kinds of a given domain of knowledge – both of which occupy a preliminary stage in his account of philosophical inquiry. As to the second question, I claim that the evidence for seeing collection and division as a formal method is weak. Although Plato calls the procedure a technê and a methodos, he makes no real attempt to formalize it in any way. For Plato, collection and division do not constitute an algorithmic process that can be learned from a rule book. Instead the ability to collect and divide properly are skills that good dialecticians must acquire through the kind of hands-on training illustrated by the Sophist and Statesman. Whereas Aristotle insists on formal rules for making proper divisions, Plato seems to emphasize the need to recognize where the natural joints of the world are. In this sense, Plato’s Sophist and Statesman and Aristotle’s Topics and Analytics present two very different pictures of collection and division.

In this paper I examine the role of optimality reasoning in Aristotle’s natural science. By “optimality reasoning” I mean reasoning that appeals to some conception of “what is best” in order to explain why things are the way they are. We are first introduced to this pattern of reasoning in the famous passage at Phaedo 97b8-98a2, where (Plato’s) Socrates invokes “what is best” as a cause (aitia) of things in nature. This passage can be seen as the intellectual ancestor of Aristotle’s own principle, expressed by the famous dictum “nature does nothing in vain but always what is best for the substance from among the possibilities concerning each kind of animal” (Progression of Animals II, 704b12-18). The paper is focused around exploring three questions that arise in connection with Aristotle’s use of this optimality principle: (1) How do we understand the concept of “the best” at work in the principle? (2) How does Aristotle conceive of “the range of possibilities”? And, finally, (3) what role does optimality reasoning play in Aristotle’s natural science? Is it a special form of demonstration in which the optimality principle functions as one of its premises, or is it a heuristic device that helps uncover those causally relevant features of a natural substances that ultimately serve as middle terms in demonstrations? In the final section I return to the comparison between Plato and Aristotle and argue that, while both see the natural world as the product of an optimizing agent and while both see this assumption as licensing a pattern of reasoning that appeals to a certain conception of “the best”, they disagree fundamentally over what the optimization agent is and how it operates. Thus, despite their general agreement, it would be a mistake to think that Aristotle simply took over Plato’s use of optimality reasoning without significant modifications.

In this paper I address an important question in Aristotle’s biology, What are the causal mechanisms behind the transmission of biological form? Aristotle’s answer to this question, I argue, is found in Generation of Animals Book 4 in connection with his investigation into the phenomenon of inheritance. There we are told that an organism’s reproductive material contains a set of "movements" which are derived from the various "potentials" of its nature (the internal principle of change that initiates and controls development). These movements, I suggest, function as specialized vehicles for communicating the parts of the parent’s heritable form during the act of reproduction. After exploring the details of this mechanism, I then take up Aristotle’s theory of inheritance proper. At the heart of the theory are three general principles (or 'laws') that govern the interactions between the maternal and paternal movements, the outcome of which determines the pattern of inheritance for the offspring. Although this paper is primarily aimed at providing a detailed analysis of Aristotle’s account of inheritance, the results of that analysis have implications for other areas of Aristotle’s biology. One of the most interesting of these is the question of whether Aristotle’s biology is anti-evolutionary (as traditionally assumed) or whether (as I argue) it leaves room for a theory of evolution by natural selection, even if Aristotle himself never took that step.