 The first kind of evidence consists of passages introducing his biological investigations that appear to make explicit reference to the account of scientific knowledge in APo. The following passage from the History of Animals (a better though less familiar translation would be Animal Inquiries), for example, suggests that the entire biological project is organized in accordance with the theory of inquiry developed in APo. II. This passage comes near the end of chapter six in the first book of HA. After five chapters in which Aristotle lays out the kinds of similarities and differences among animals to be studied and sketches the ways in which they are to be investigated, he makes the following programmatic statement about the investigation to come, and where it fits in the entire scientific study of animals.