Biology and theology are interdependent theoretical sciences for Aristotle. In prominent discussions of the divine things (the stars and their unmoved movers) Aristotle appeals to the science of living things, and in prominent discussions of the nature of plants and animals Aristotle appeals to the nature of the divine. There is in fact a single continuous series of living things that includes gods, humans, animals, and plants, all of them living and, in a way, divine. Aristotle has this continuum of divine beings, and a theory of value that corresponds to it, in mind not only in key parts of his theology and natural science (including astrophysics and biology), but also in his practical philosophy. Here I can do little more than call attention to some important texts and attempt to offer a coherent account of them, without being able to enter into the usual interpretive disputes. I begin by clarifying the terms “theology” and “biology” and their place in Aristotle’s division of philosophy. Next, I discuss how Aristotle’s theology is informed by his biology, and then how his biology is informed by his theology. I end by discussing some implications of the interdependence of biology and theology for Aristotle’s ethics and exhortation to philosophy.

Aristotle is a political scientist and a student of biology. Political science, in his view, is concerned with the human good and thus it includes the study of ethics. He approaches many subjects from the perspective of both political science and biology: the virtues, the function of humans, and the political nature of humans. In light of the overlap between the two disciplines, I look at whether or not Aristotle’s views in biology influence or explain some of his theses in political science. I show that we should not seek a unified answer to this question, for the relationship between the two disciplines varies depending on the topic. In some cases, for example the nature of the human function, the biological background is likely to be endorsed as one of the presuppositions of the ethical enquiry. In other cases, for example the study of social hierarchies, even though the ethical works and the biological works come to similar conclusions, it is hard to establish that the biological approach is intended to provide support to the ethico-political approach. In conclusion, I show that Aristotle’s political science and his biology are in conflict at least in two important cases: his account of justice towards nonhuman animals and his exhortation to contemplate.

Aristotle’s biology and contemporary evolutionary biology appear to be fundamentally at odds. Any comparative biology seeks to explain the fit and diversity of organismal form, but Aristotelian and contemporary biology do so in very different, evidently incompatible, ways. In this chapter, I argue for a reconciliation between the two biologies. Recent advances in evolutionary thinking suggest that the form of population thinking pursued by twentieth-century evolutionary biology must be augmented by an understanding of the ways in which organisms as adaptive, purposive entities contribute to adaptive evolution. Moreover, the phenomenon of adaptation cannot adequately be understood unless we take into account the ways in which an organism’s “way of life” structures its experience of its conditions of existence. The active role that organisms play in evolution is nicely captured in Aristotle’s concept of bios – way of life.

Chapter Summary. Part i made a case for seeing the Posterior Analytics ii in a new light. In that new light, it does not provide poor answers to questions people bring to it about the path by which inquiry takes us from perceptual experience to first principles of demonstration. Rather it provides very good answers to questions about what questions ought to shape any inquiry aimed at knowledge and about how the answers to those questions are related to one another – it provides, that is, an erotetic framework for inquiry. Many of the norms that guide scientific inquiries, however, are domain-specific, and are not to be found in APo., though they are best seen as different ways of specifying the framework provided by the Analytics.

Chapter Summary. In this chapter and the next I explore the ways in which Aristotle uses the results of one natural inquiry as starting points for inquiry in another area. This is a practice in which Aristotle routinely indulges, and yet there is, at least prima facie, a problem with him doing so, given his views about how we arrive at first principles and the propriety of those principles to specific domains. In APo. i.7–13, he allows that geometric and arithmetic premises can be used in a range of fields of inquiry he refers to as ‘subalternate’ branches of mathematics, which he elsewhere describes as ‘the more natural of the mathematical sciences’ (i.e., optics, astronomy, mechanics, and harmonics). However, whether and, if so, how this practice might apply within the science of nature is never explicitly addressed. In this chapter, I address this question by exploring the dependence of Aristotle’s discussion of the application of the concepts ‘right’ and ‘left’ to the motions of the heavens on his discussion of directional dimensions in De incessu animalium.

Chapter Summary. The long, introductory chapter of the De anima provides a detailed and complicated erotetic structure for a norm-governed inquiry into the soul. Answering the complex list of questions laid out in that chapter provides the norms that govern Aristotle’s critical discussion of his predecessors in de An. i and his own positive account of the soul in de An. ii–iii. In this chapter, I will begin with a careful study of that introductory chapter from the standpoint of what we can learn about Aristotle’s methodos for an inquiry into the soul, and then turn to a study of the way in which the norms derived from answering the questions laid out in de An. i.1 govern the inquiry that ensues. One surprising result of this study is that, contrary to a widespread assumption, the de An. is, for good reason, not simply one of a number of contributions to natural science.

Chapter Summary. Metaph. Ε.1 provides a deceptively clean map of scientific knowledge, differentiating three forms of theoretical knowledge (first philosophy, mathematics, natural science) from each other and theoretical knowledge as a whole from practical and productive knowledge. The focus of this chapter will be on natural science (ἡ φυσικὴ ἐπιστήμη, 1025b19), considered as the ultimate goal of natural inquiry. Given the results established up to this point about Aristotle’s general account of inquiry, my aim in this chapter is to answer two related, more specific questions about natural inquiry

One should explain in the following way, for example, breathing exists for the sake of this, while that comes to be from necessity because of these. But ‘necessity’ sometimes signifies that if that – that is, that for the sake of which – is to be, it is necessary for these things to obtain, while at other times it signifies that things are thus in respect of their character or nature. For it is necessary for the hot to go out and enter again upon meeting resistance, and for the air to flow in. This is directly necessary; and it is as the internal heat retreats during the cooling of the external air that inhalation and exhalation occur. This then is the manner of proper inquiry, and it is concerning these things and things of this sort that one should grasp the causes.

Chapter Summary. Book i of the Posterior Analytics articulates necessary and sufficient conditions for the achievement of unqualified scientific knowledge, among which is being in possession of first principles of demonstration that themselves are indemonstrable. Book ii, an investigation of inquiries leading to knowledge of essences and causes, describes stages on the way to that goal, each stage looked at from two different perspectives: definitions expressing knowledge of essences and demonstrations expressing knowledge of causes. It has proven difficult to read this second book as a unified discussion, and that has led to a great deal of literature focused almost exclusively on its last chapter, on the assumption that this is where Aristotle provides his answer to the question of how we achieve knowledge of those indemonstrable first principles. But the description of that process in ii.19 is widely viewed as insufficiently robust to explain how first principles arrived at by such a process could possess the epistemic authority Aristotle claims for them.

Dante refers to Aristotle as “il maestro di color che sanno,” the master of those who know. But Aristotle typically refers to the works that have come down to us as ‘inquiries’ or ‘investigations,’ and in the pages that follow, I will make a case for Aristotle as “il maestro di color che cercano,” the master of those who inquire. The chapters to follow attempt to get clarity on Aristotle’s conception of inquiry, insofar as the goal of inquiry is scientific knowledge (ἐπιστήμη). Does Aristotle see inquiry, as he clearly sees explanation, as a process constrained by epistemic norms – norms of inquiry, as I am calling them? That is, given that Aristotle has clearly articulated ideas about what the goal of scientific inquiry looks like, does he also have clearly articulated norms that must be adhered to if one is to achieve that goal?