What is it about lemons?

Thomas Nagel

  • The Quest for Reality: Subjectivism and the Metaphysics of Colour by Barry Stroud
    Oxford, 228 pp, £19.99, January 2000, ISBN 0 19 513388 9

This strange and absorbing book sets out to undermine the central metaphysical ambition which has dominated philosophy since the 17th century – that of reaching what Bernard Williams calls an ‘absolute conception of reality’. The aim is to achieve a comprehensive understanding of the world, consistent with modern science, which distinguishes between what exists objectively, independent of our minds, and what is merely subjective – due to the effects of the world on our minds and our responses to it.

In resisting the metaphysical conclusions that result from this quest, Barry Stroud writes against the temper of the times, and very much in the spirit of the later Wittgenstein, who was also self-consciously out of step with the times, and who remains for the most part unassimilated by contemporary philosophy, in spite of being conventionally venerated as one of the few great philosophers of the 20th century. Stroud’s philosophical style, however, except for its lack of ornament and strict avoidance of technical language, is completely unlike Wittgenstein’s, which was gnomic and indirect. Stroud is clear, explicit, methodical and relentless. He tries to block every exit, and to say exactly what has been shown and what has not. The result is deliberately frustrating, for his aim is to baffle a desire for understanding of our true relation to the universe that is at the root of philosophy and that Stroud himself recognises we cannot get rid of.

Like all of his writings – on scepticism, on Hume, on Kant, on Wittgenstein – The Quest for Reality displays a profound grasp of the history and logical structure of philosophical problems and theories, and a feeling for the derangement of thought that underlies them. He insists that the understanding sought by metaphysics is distinct from scientific understanding, for we could attain it only by answering a question which remains after all scientific results are in. Yet the metaphysical outlook he wants to resist arose and continues to be widely accepted because it seemed to so many people obvious from the beginning that the results of modern physical science reveal a distinction between subjective appearance and objective reality, one which demands formulation as a comprehensive philosophical worldview. Before explaining why Stroud believes that this is not the case, let me describe the view more fully.

The new science of the 17th century was brought into existence when Galileo and Newton developed a quantitative geometrical understanding of the physical world and the laws governing it, a description that left out the familiar qualitative aspects of things as they appear to the separate human senses: their smell, taste, sound, feel and colour. Colours and smells did not enter into physics, and in spite of the look and aroma of a typical chemistry lab, they didn’t enter into chemistry either, when it subsequently developed into a theory of the true composition of everything around us from a limited number of elements. Stroud quotes Galileo: ‘If the ears, the tongue, and the nostrils were taken away, the figure, the numbers and motions of bodies would indeed remain, but not the odours or the tastes or the sounds, which, without the living animal, I do not believe are anything else than names.’ This view was taken up by Descartes, and then enshrined by Locke as the now familiar distinction between primary and secondary qualities – the primary qualities of size, shape and motion being those that belong to things as they are in themselves, and the secondary qualities of colour, sound, taste, feel and smell being mere appearances, produced by the action of these things on our senses.

This conception of the world, as Stroud says, ‘came to seem like nothing more than scientifically enlightened common sense’. And it has survived changes in physical science that have long since rendered obsolete the original catalogue of primary qualities. A modern Locke has to accommodate charge, spin, superstrings and space-time of many more than three dimensions, but the idea is the same: the physical world as it is in itself is describable in quantitative, spatiotemporal terms; everything else we say about it depends on how it affects us or how we react to it. Objective, mind-independent reality is the now totally unfamiliar world described by a rapidly developing physics; the familiar world that we live in, from colours to values, is subjective and mind-dependent.

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