Online research in philosophy

The first half of this review article on Locke on primary and secondary qualities leads up to a fairly straightforward reading of what Locke says about the distinction in Essay II.viii, one that, in its general outlines, represents a sympathetic understanding of Locke’s discussion. The second half of the paper turns to consider a few of the ways in which interpreting Locke on primary and secondary qualities has proven more complicated. Here we take up what is sometimes called the Berkeleyan interpretation of Locke (section 6), the understanding of Locke’s resemblance thesis (section 7), and Locke’s views of qualities and their relationship to powers (section 8).

Many philosophers have maintained that secondary qualities are private mental entities. In this paper I use the discussions of H. A. Prichard, Berkeley and G. E. Moore on the status of secondary qualities to bring out the assumptions that underlie this view. One of these is that secondary qualities are particular. I show that Prichard holds these assumptions and then I attempt to diagnose why he holds them. In the course of this diagnosis I explore several senses of 'dependent' which play a role in this view. Finally, I show that a causal dependence of secondary qualities upon the perceiver will not lead to the conclusion that secondary qualities are private unless the philosophical thesis that they are particular is already assumed.

In this paper, I argue that Book II, Chapter viii of Locke' Essay is a unified, self-consistent whole, and that the appearance of inconsistency is due largely to anachronistic misreadings and misunderstandings. The key to the distinction between primary and secondary qualities is that the former are, while the latter are not, real properties, i.e., properties that exist in bodies independently of being perceived. Once the distinction is properly understood, it becomes clear that Locke's arguments for it are simple, valid and (in one case) persuasive as well.

Reid offers an under-appreciated account of the primary/secondary quality distinction. He gives sound reasons for rejecting the views of Locke, Boyle, Galileo and others, and presents a better alternative, according to which the distinction is epistemic rather than metaphysical. Primary qualities, for Reid, are qualities whose intrinsic natures can be known through sensation. Secondary qualities, on the other hand, are unknown causes of sensations. Some may object that Reid's view is internally inconsistent, or unacceptably relativistic. However, a deeper understanding shows that it is consistent, and relative only to normal humans. To acquire this deeper understanding, one must also explore the nature of dispositions, Reid's rejection of the theory of ideas, his distinction between sensation and perception, and his distinction between natural and acquired perceptions.

The Dangerous Book for Boys Abstract: Seventeenth and eighteenth century discussions of the senses are often thought to contain a profound truth: some perceptible properties are secondary qualities, dispositions to produce certain sorts of experiences in perceivers. In particular, colors are secondary qualities: for example, an object is green iff it is disposed to look green to standard perceivers in standard conditions. After rebutting Boghossian and Velleman’s argument that a certain kind of secondary quality theory is viciously circular, we discuss three main lines of argument for the secondary quality theory. The first is inspired by an intuitively compelling picture of perception articulated by Reid; the second is that the secondary quality theory is a conceptual truth; the third line of argument is presented in Johnston’s influential paper ‘How to speak of the colors’. We conclude that all these arguments fail, and that the secondary quality theory is unmotivated. Keywords: color, secondary quality, disposition, vision, perception..

For Locke, an idea is ‘the immediate object of perception, thought, or understanding’ (§8).1 Perhaps this is something like a concept: he goes on to give examples of white, cold, and round, which look like they have some representational content. What do these ideas represent? Locke defines a quality: ‘the power to produce any idea in our mind, I call quality of the subject wherein that power is’ (§8). The natural thought is that these ideas represent some quality of the object, which quality just is the power that the object has to produce that idea in us. Though the idea is in us, the power or quality is clearly in the object. Sometimes, it is true, we speak loosely and refer to the quality of the object by the same name that we use to refer to the idea in us, and talk of white being in the object, for example. Locke cautions that when we speak like this, we should ‘be understood to mean those qualities in the objects which produce them [the ideas] in us’ (§8).