Ideas, Reason, and Skepticism: Replies to my Critics

Abstract

Ideas Wilson raises two main questions about Hume's theory of abstract or general ideas. According to that theory, an abstract idea is a determinate idea of an exemplar, associated with a general term that disposes the mind to call up, as needed, any of what I called a of ideas of other exemplars. Her first question is this: Given the essential roles played by the general term and the revival set in fixing the meaning of an abstract idea, how important is the determinate idea that actually serves as the abstract idea itself? From a purely logical standpoint, Hume must agree that the determinate idea serving as the abstract idea itself is no more important than any other member of the revival set: for that idea could be relegated to the revival set and replaced by one of the members of that set without changing in any way the meaning of the word. Indeed, different people, and even the same person at different times, can use different ideas for this purpose. Still, he does say that we always invoke one.3 Here is one reason why he might think the occurrence of such an idea is important from a psychological standpoint. When he describes the role of the revival set in general judgments, it is always as a source of counterexamples. Thus, whenever we dissent from a general claim (i.e., a universal generalization), it is because we recall a counterexample from the revival set that is, associated with a general term, a counterexample whose conception induces or constitutes dissent. Hence, when we assent to a general claim, it is presumably because no counterexample from the revival set comes to mind. But belief, for Hume, consists in the liveliness of some idea. So we still need at least one idea actually before the mind whose liveliness can constitute belief in the general claim affirmed; and it may well be that one important intended purpose of the exemplar serving as the abstract idea is to play this role. The second question about Hume's theory of abstract ideas is this: How determinate must ideas be? As Wilson herself rightly suggests, Hume's short answer to this question will be that ideas must be exactly as determinate as impressions must be, since ideas differ from impressions in force and vivacity but not in content or logical character. For example, a visual idea must be determinate in the sense that the minima imaginabilia composing it each have a determinate color and occupy determinate spatial positions relative to one another—just as a television image must be determinate in Volume XXIV, Number 1, April 1998