The general theory of science outlined in Aristotle’s Posterior Analytics mandates that the scientific enterprise proceeds in stages, and that the two main stages of any scientific inquiry are the collection of the relevant data followed by their explanation – the pre-explanatory and the explanatory stages of inquiry, respectively. Aristotle’s study of animals illustrates this methodological insight in an especially clear way. Moreover, the following epistemic principle controls Aristotle’s study of animals: the study of animals must start from the most organized and most determinate form of life and must take that as its starting point to generate results that can be subsequently extended to what is comparatively less organized and less articulate. This means that the study of animals must begin with a discussion of the human body. This methodological insight is at work in Aristotle’s History of Animals. However, its significance goes well beyond the stage of the collection and presentation of the relevant data; this chapter shows that this rule of inquiry also shapes the explanation of the zoological data in Parts of Animals, Progression of Animals, and Generation of Animals. The chapter also discusses the distortions created by the application of this rule of inquiry with a concentration on Aristotle’s explanation of animal locomotion.

Theophrastus shares Aristotle’s methodological insight that the scientific inquiry unfolds in stages, and that the two main stages of any scientific inquiry are the collection of the relevant data followed by their explanation – the pre-explanatory and the explanatory stage of inquiry, respectively. This chapter shows that we should speak of two main stages of inquiry because the explanatory stage itself may unfold in various stages. In other words, the work that is required to arrive at an adequate (i.e., scientific) explanation may take place in steps and may require accomplishing different tasks. The chapter looks in some detail at how Theophrastus adopts this style of inquiry in his explanation of the various ways in which plants propagate.

This chapter compares Aristotle’s theory of generation and Darwinian evolution by natural selection. It begins by explicating Aristotle’s distinction between intrinsic (kat’auta) and incidental (kata sumbêbêkos) final causation. Aristotle uses this distinction to differentiate Empedocles’ account of generation as incidentally final from his own intrinsically final view. Like Empedocles, Aristotle accepts spontaneous generation, but only as an exception to formal, sexual reproduction. In consequence, he describes spontaneous generation differently from Empedocles.

The chapter goes on to argue that by these standards Darwinian natural selection is intrinsically final and biologically (but not cosmologically) teleological. Accordingly, it is not nearly as similar to Empedocles’ primitive theory of “natural selection” as is sometimes assumed. That this difference was not apparent to Darwin’s contemporaries, or even to Darwin himself, is attributed to Darwinism’s subtle mixture of chance, determinism, and biological teleology. At first, the effects of medieval creationism on Aristotle’s hylomorphism and deterministic views about science were prominent factors standing in the way of understanding the logic of adaptive natural selection. Mid-twentieth-century Neo-Darwinism made the telic logic of Darwinian adaptation more perspicuous. Recent developments in regulatory genetics promise to give evolutionary meaning to something akin to Aristotle’s epigenetic account of generation.

Aristotle divides the physical world between a celestial realm, which is alive but neither hot nor cold, and a sublunary realm, which is moved by heat in two forms: the vital heat of the biological works and the inanimate fire, the operation of which is explained in the Meteorologica. In the context of the second division we find Aristotle distinguishing between the macrocosm (roughly the world according to Physics, de Caelo, Generation and Corruption and the Meteorologica) and the microcosm (the realm of the biological works, the individual sublunary animals). Wilson argues that this second division does not overturn the first one, but rather complements it, for it has some bearing on the question of solar and vital heat. He further argues that Aristotle mediates the macrocosm and the microcosm through the conceptual apparatus of the spontaneous generation in which heat plays a manifest role.