Hume on Qualities

Hume Studies Volume XXII, Number 1, April 1996, pp. 49-88 Hume on Qualities PHILLIP D. CUMMINS This paper is an attempt to ascertain whether Hume's three approaches to the distinction between simplicity and complexity in Book One of A Treatise of Human Nature1 can be integrated into a consistent whole. The consistency issue will be focused on Hume's position concerning the status of qualities. I. Types of Complexity and Simplicity In the opening section of the Treatise Hume introduced a distinction between simple and complex perceptions and provided definitions for both. He wrote: There is another division of our perceptions, which it will be convenient to observe, and which extends itself both to our impressions and ideas. This division is into SIMPLE and COMPLEX. Simple perceptions or impressions and ideas are such as admit of no distinction nor separation. The complex are the contrary to these, and may be distinguished into parts. Tho' a particular colour, taste, and smell are qualities all united together in this apple, 'tis easy to perceive they are not the same, but are at least distinguishable from each other. (T 2) Though hardly a systematic explication of the distinction between simple and complex perceptions, this is a beginning. Complexity is to be understood in terms of internal diversity (distinctness, distinguishability, and separability of Phillip D. Cummins is at the Philosophy Department, University of Iowa, 269 English Philosophy Building, Iowa City, Iowa 52242-1408 USA. email: pcummins@blue.weeg.uiowa.edu 50 Phillip D. Cummins parts) and simplicity on its denial. Hume's example is not helpful, since to the uninitiated—those who have read neither Locke nor Berkeley—calling its colour a part of an apple would be extremely puzzling. The distinction is employed immediately, because several important Humean principles hold only for simple perceptions. For example, blocked by obvious counterexamples from expanding its scope to cover complex perceptions, Hume confidently asserted the principle that "every simple idea has a simple impression, which resembles it; and every simple impression a correspondent idea" (T 3). Noting the priority of simple impressions to their corresponding simple ideas, Hume further maintained, "...All our simple ideas in their first appearance are deriv'd from simple impressions, which are correspondent to them, and which they exactly represent" (T 4, emphasis Hume's). This familiar causal claim plays a well-known and important role in Hume's treatment of ideas, so it is appropriate to consider further what I shall call conceptual simplicity and complexity, the sense of the simple/complex distinction on which it is founded. In his Essay concerning Human Understanding, Locke contrasted definable to indefinable words and specified a sense of simplicity for ideas that he correlated with the indefinability of the words expressing them.2 An idea is simple if and only if the word or words used to express it are indefinable. Otherwise, it is complex. It seems to me that the sense of the word 'idea' operative when Locke drew this distinction is that of "concept"; ideas in this sense are employed in recognizing objects as well as in thinking about them in their absence. So understood, ideas are intentional; each has an object distinct from itself. The object of an idea is what that idea is of. Thus, the object of somebody's idea of pain is pain and the object of the idea of squareness is squareness. There is, therefore, some basis for saying that the simplicity or complexity of an idea just is the simplicity or complexity of its object. There is then the following order: simple object, simple idea, indefinable word. A question remains: what is it for the object of an idea to be simple? One could answer that a simple object is an object which does not have other objects as parts, just as one could have asserted that a simple idea is an idea which does not have other ideas as parts. This answer provokes a further question: what indicates that an object lacks object-parts? One answer is: its unanalyzability. This flirts with circularity, but still seems right. To have the concept of some object is to know what it is.3 A simple...