17. Teleology

Aristotle had a teleological view of nature. Natural behaviour and natural structure usually have final causes, but these are constrained by necessity: nature does the best she can ‘in the circumstances’. Aristotle’s teleology is sometimes summed up in the slogan ‘Nature does nothing in vain’, and he himself frequently uses similar aphorisms. ‘Nature does nothing in vain’ is a regulative principle for scientific enquiry. ‘Teleology’ asserts that, even though Aristotle knew that some aspects of nature are functionless, he recognized that a grasp of function is crucial to understanding nature. References to the prudence of nature are not childish superstition, but reminders of a central task of the natural scientist.

8. Knowledge

Whereas the Prior Analytics derives the theorems of a science from its axioms, the Posterior Analytics is concerned with the nature of the axioms themselves, and hence the general form of an axiomatized deductive science. A science is meant to systematize our knowledge of its subject-matter, so its component axioms and theorems must be propositions which are known and satisfy the conditions set upon knowledge. ‘Knowledge’ reveals these. The first condition is one of causality. Clearly, the axioms must be true. Equally clearly, they must be ‘immediate and primary’. The axioms must be ‘more known’ than the theorems and, finally, they must be ‘prior to and causes of the conclusion’.

2. A Public Figure

‘A public figure‘ discusses Aristotle’s second period in Athens, the cultural capital of the Greek world. He taught regularly in the Lyceum, believing that knowledge and teaching were inseparable. His own researches were frequently carried out in a research team and his results communicated to his friends and pupils. By the 330s, he clearly had some reputation as a scholar since he was invited to draw up the victory lists at Delphi, a task requiring historical research. Other historical projects include the Constitutions of States, which included a brief constitutional history of Athens, and a descriptive survey of Athenian political institutions. In 322 BC Aristotle left Athens for political reasons.

20. Afterlife

‘Afterlife’ argues that an account of Aristotle’s intellectual legacy would amount to a history of European thought. Aristotle’s various doctrines and beliefs were accepted and taught as truths, influencing philosophy, science, history, theology, poetry and drama. He founded the science of biology, setting it on a sure empirical and philosophical basis. In logic too, Aristotle founded a new science, and his logic remained until the end of the last century the logic of European thought. While Aristotle’s biology and logic are outdated, the same is not true of his more philosophical writings. Finally, Aristotle set before us, explicitly and implicitly, an ideal of human excellence.

15. Psychology

One important distinction within the natural world is that some natural substances are alive and others inanimate. The former are distinguished from the latter by their possession of a soul or animator. ‘Psychology’ explains that Aristotle’s souls are not pieces of living things or bits of spiritual stuff inside physical bodies; rather, they are sets of powers or capacities. Souls are fulfilments of bodies and cannot exist independently. Aristotle’s treatment of thought is both obscure in itself and hard to reconcile with the rest of his psychology. However, that should not detract from his work on psychology, which is persistently scientific in its approach.

13. Empiricism

‘Empiricism’ stresses that, for Aristotle, knowledge or science ultimately derives from perception. That is the source of the concepts in terms of which we seek to understand reality. Knowledge is not the same as perception, but is bred by generalization out of perception. This raises questions. Is sense perception reliable? How can we tell? How can we distinguish illusion from genuine perception? Are we justified in moving from particular observations to general truths? How can we know if our observations are sufficiently numerous or representative? Aristotle is dismissive of the sceptics in the Metaphysics: he thinks their views are not seriously held and need not be taken seriously.

11. Change

Unlike Plato’s Forms, which are eternal and unchanging, Aristotle’s substances are temporary and undergo alterations. Aristotle considered there to be four types of change: in respect of substance, quality, quantity, and place. These are generation or destruction; alteration; growth and diminution; and motion, respectively. Most of the Physics is devoted to change in its different forms. Change takes place in time and space, and the Physics offers intricate theories about the nature of time, of place, and of empty space. Since space and time are infinitely divisible, Aristotle analyses the notion of infinity. He also discusses a number of particular problems concerning the relation of motion to time.

10. Reality

Science is about real things. That is what makes it knowledge rather than fantasy. But what things are real? What are the fundamental items with which science is concerned? That is the question of ontology, to which Aristotle devoted much attention. One of his ontological essays, the Categories, is relatively clear; but most of his ontological thought is to be found in the more obscure Metaphysics. ‘Reality’ attempts to determine what Aristotelian substances are. The first and plainest examples of substances are animals and plants and perhaps also artefacts. In general, perceptible things — middle-sized material objects — are Aristotle’s basic realities and the things with which science is principally concerned.

6. The Structure of the Sciences

Aristotle did not share Plato’s belief that all knowledge could be founded upon a single set of axioms. ‘The Structure of the Sciences’ shows that Aristotle divided knowledge into three major classes. The productive sciences are concerned with making things; Aristotle himself had relatively little to say about these. The practical sciences are concerned with how we ought to act in various circumstances, in private and public affairs. The Ethics and the Politics are Aristotle’s chief contributions here. Theoretical knowledge includes everything now considered science, and in Aristotle’s view it contains most of human knowledge. It subdivides into mathematics, natural science, and theology (closer in practice to astronomy).

5. The Philosophical Background

‘The Philosophical Background’ focuses on the influence of Plato on Aristotle. Aristotle was a systematic thinker, and shared Plato’s vision of a unified theory of science. While Aristotle indisputably turned logic into a science and invented the discipline of formal logic, Plato had initiated enquiry into the foundations of logic and expected his pupils to train themselves in argumentation. Aristotle did not accept Plato’s theory of Forms, but it influenced his own numerous efforts to develop an alternative ontology. In Plato’s view, the notions of science and knowledge were intimately tied to that of explanation – a concern inherited by Aristotle, who also shared his master’s interest in epistemological discussion.