In ‘Aristotle on the Stages of Cognitive Development’, Thomas Kjeller Johansen examines Aristotle’s contributions to our thinking about concepts from a different perspective, namely in connection to Aristotle’s psychology. He revisits Aristotle’s account of how we acquire universal concepts mainly on the basis of Metaphysics A.1, Posterior Analytics 1.31 and 2.19, and the De Anima. The chapter begins by articulating the following puzzle. On the one hand, Aristotle points out (An. Post. 1.31, 2.19) that we perceive the universal in the particular. On the other, he suggests (Metaph. A.1) that it is only when we have craft and science that we grasp the universal, while perception, memory, and experience all are concerned with the particular. Building on the widespread view that, according to Aristotle, the universal grasped in craft and science is the universal cause, Johansen argues that we should understand perception, memory, and experience teleologically, as stages in the ordering of perceptual information that allows this causal concept to emerge.

The Introduction sets the scene by addressing first the problems involved with translating the term technê and related issues with circumscribing the Greek concept. The social context of craft and craftsmen is briefly discussed. Criteria for technê are outlined, with the importance of the Hippocratic writings for Plato and Aristotle highlighted. The central role of technê as a model of knowledge is introduced, and its applications to a range of disciplines, including ethics, politics and cosmology.

This chapter discusses the use of technê to characterize the creator god in Plato’s Timaeus. Timaeus explains how a divine craftsman, the Demiurge, made the whole cosmos as a living being. He created the heavenly bodies, but left the creation of human and other mortal beings to these ‘lesser’ gods. But if the Demiurge was the best of all craftsmen, seeking to make the finest cosmos possible, why did he not make the mortal beings too? Having outlined Plato’s conception of craft, Johansen explains how this problem, which he calls the ‘technodicy’, arises for Timaeus, contrasting it with the classical theodicy. The Demiurge’s creation is limited by his craft. Timaeus therefore assigns another craft to the lesser gods to produce mortal beings. However, even this craft prevents the lesser gods from directly producing non-human animals, and so the problem is reiterated. The issue is sought to be resolved by making humans themselves responsible for their own reincarnation as lower animals. Timaeus’ position is comparable to the view in Laws X: the lesser gods, consistent with their role as craftsmen, have overall responsibility for the organization of lower kinds of living being, without causing any particular beings to belong to particular kinds.

A teleological explanation is an explanation in terms of an end or a purpose. So saying that ‘X came about for the sake of Y’ is a teleological account of X. It is a striking feature of ancient Greek philosophy that many thinkers accepted that the world should be explained in this way. However, before Aristotle, teleological explanations of the cosmos were generally based on the idea that it had been created by a divine intelligence. If an intelligent power made the world, then it makes sense that it did so with a purpose in mind, so grasping this purpose will help us understand the world. This is the pattern of teleological explanation that we find in the Presocratics and in Plato. However, with Aristotle teleology underwent a change: instead of thinking that the ends were explanatory because a mind had sought to bring them about, Aristotle took the ends to operate in natural beings independently of the efforts of any creative intelligence. Indeed, he thought that his predecessors had failed to understand what was distinctive of nature, namely, that its ends work from the inside of natural beings themselves.

One of the basic puzzles of the Timaeus-Critias concerns the thematic unity of the dialogue. Why is the bulk of the dialogue taken up with a discussion of natural philosophy when it apparently sets out simply to give an account of a war between Atlantis and ancient Athens? What, if anything, does natural philosophy have to do with war?

The Timaeus-Critias is presented as a continuation of the Republic. Socrates begins by reporting a conversation he had yesterday, in which he described a constitution (politeia) which in outline matches that of the Republic. He now expects his listeners from yesterday to repay him in kind. Here is what he wants:

At the beginning of the Timaeus-Critias Socrates likened himself to a spectator wishing to observe beautiful animals in motion. At the end of the work the world and its denizens have been shown to be just that. The cosmos itself is a beautiful animal moving in time and space and it is composed of animals, planets, humans, and other animals, whose design displays the greatest possible rationality. Even the city and its actions can be understood by its place within the greater cosmic order. As readers we are placed in the position of observers of a cosmos which, like that famously presented on the shield of Achilles in Iliad 18 and reconstructed on the cover of this book, invites us to understand our role as human beings and citizens by inclusion in a world order. If this is the world we live in, if this is how nature works, then we should arrange our lives accordingly. The Timaeus-Critias coaxes us into adopting an ordered life, not by knockdown argument, but by showing our place in a picture. It is the detail and completeness of this picture that draw us in. Cosmology plays an important role here particularly for those of us who have not been brought up in a well-ordered city and who therefore lack first-hand experience of paradigms of good order.

Chapter 1 argued that the connection between the Atlantis story and Timaeus' cosmology lies in teleology. Nature in general and human nature in particular are geared towards the good. We acted against nature if we chose a life of injustice and could expect to suffer for it, whilst a life of justice would be rewarded with happiness in this life as in the afterlife. In chapter 2 I considered the Atlantis story and argued that it is a story about the actions of good men, of the sort envisaged by the Republic. We were warned not to take the story as a historical representation, but as a true story in the sense that it correctly represents how good people would prevail in war.

In this chapter I turn to the status of Timaeus' account. Timaeus famously describes the status of his account as an eikōs muthos or as an eikōs logos, that is, as a likely story or myth or as a likely account. This description occurs as the conclusion of the methodological passage at the beginning of Timaeus' speech. Timaeus will later litter his account with reminders that his account is likely. There is therefore no doubt that he means us to pay close attention to this passage. This chapter focuses on the two major questions we face when assessing the status of Timaeus' account. What does he mean by calling his account ‘likely’ and why does he call it alternately a likely muthos and a likely logos?

For Timaeus, as we saw in the last chapter, the world is a product of craftsmanship. However, craftsmanship is not the only cause of the cosmos. Another is ‘necessity’. The introduction of this cause occasions Timaeus to make a fresh beginning to his cosmology at 47e3–48b3:

It should perhaps come as no surprise to us that the demiurge needed another principle apart from reason when he fashioned the universe.

I start with Cornford's diagnosis of Plato's view of the perceptible world and perception. Cornford reacted with justification against Taylor's assimilation of Timaeus to a modern positivistic view of science. Taylor had suggested that the status of our accounts of the natural world as merely likely could ultimately be overcome with the progress of empirical science. The Timaeus story was for Taylor a myth only ‘in the sense that it is the nearest approximation which can “provisionally” be made to exact truth’.Cornford was surely right to object that our accounts could in principle only ever be likely in so far as they are accounts of a likeness.

Cornford's and Taylor's positions are contraries but not contradictories. For whilst mutually exclusive, they are not jointly exhaustive. Whilst Taylor gives too much to perception, I want to argue that Cornford gives too little. In natural philosophy perception stands in a complex interactive relationship with reason. It is the aim of this chapter to analyse this relationship.