This chapter contains an outline of the book and of its main argument. It concentrates on the deep structure of the Peripatetic science of perishable living beings, which consists in separate but coordinated studies of animals and plants. It provides the reader with an initial idea of the contents of the book with an emphasis on the epistemic requirements that shape the Peripatetic study of perishable life.

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.

The first and most important step into the Peripatetic study of living beings is the observation that life takes many forms. In the sublunary world, it takes the form of plant and animal life (with human life as a special kind of animal life). When Aristotle and Theophrastus speak of animals and plants, they never assume that they are a single form of life. This is confirmed by what we read at the outset of the Meteorology, where Aristotle outlines an ambitious research program that ends with separate yet coordinated studies of “animals and plants.” Whether there is unity, and how much unity there is, in these two studies remains an open question at the outset of the Meteorology. But when we look at the two corpora of writings that Aristotle and Theophrastus have left on the topic of animals and plants, we see that the unity they are able secure is limited. Last but not least, this chapter shows that the study of the nutritive soul advanced in Aristotle’s De anima cannot secure unity within the study of animals and plants.

Aristotle’s De anima provides the foundation for a theoretically informed study of perishable life on the crucial assumption that the soul is that which distinguishes what is alive from what is not. It is because Aristotle and Theophrastus take animals and plants to be different kinds of perishable living beings that they are justified in approaching the study of perishable life through separate studies of animals and plants. The chapter offers a survey of the discourse on and around life before Aristotle and Theophrastus with a focus on Plato and the doxographical information on the Presocratic investigation of nature. It also considers the way in which the study of life is narrow down to the study of perishable life, that is animals and plants, as a result of the conceptual work done in Aristotle’s De anima.

This chapter plays an important role in the argument of the book. It shows that there is room in Aristotle’s life for a study of what is common to animals and plants in addition to separate studies of animals and plants. At the same time, it shows that what Aristotle is able, or willing, to say in common for animals and plants is truly limited. By the end of the chapter the reader will see that the Peripatetic study of life is a complex scientific endeavor consisting of at least three components: a study of what is common to animals and plants followed by separate yet coordinated studies of animals and plants. What Aristotle is able, or willing, to say in common for animals and plants is to be found within the boundaries of project of the Parva naturalia.

This chapter introduces the reader to how Theophrastus approaches the topic of plants by offering a selective discussion of the first book of History of Plants. This book is a prolegomenon to the study of plants. It is also a liminal space where Theophrastus negotiates the transition from the study of animals to the study of plants. From the very way Theophrastus refers to animals, we can infer that Theophrastus builds his whole edifice on the results achieved in the study of animals. This overall approach not only confirms that the Peripatetic study of perishable living beings is approached via separate studies of animals and plants but also suggests that the relevant order of study is first animals, then plants.