Causation, Extrinsic Relations, and Hume's Second Thoughts about Personal Identity

Abstract

Causation, Extrinsic Relations, and Hume's Second Thoughts about Personal Identity Louis E. Loeb According to the account offered in Treatise 1.4.6, "Of personal identity," the identity of a mind over time consists in a sequence of perceptions related by causation. In both ofHume's two definitions of cause, causation is an external or extrinsic relation. Hume is explicit that this result is tolerable. If causation is an extrinsic relation, and personal identity is analysed in terms of causation, then personal identity is an extrinsic relation. I suggest that Hume finds this consequence intolerable, and that his finding it so is the source ofhis famous misgivings in the appendix in regard to his section on personal identity.1 In the appendix, Humeindicates that "there wou'dbe no difficulty" in regard to his section concerning personal identity, if the mind perceived some "real connexion" among perceptions.2 In book 1, however, Hume maintains that causation does not involve a real connection, and that personal identity depends on causation; and he seems content with the result that personal identity does not involve a real connection. At 1.3.14, "Ofthe idea ofnecessary connexion," Hume insists that there is no "real connexion" between causes and effects and, more generally, that there is no "real intelligible connexion" between external objects (T 168; cf. T 103). At T 169-70, he offers two ("exact") definitions of the relation of cause and effect. Hume thinks there are causes and effects, even though there are no real connections. At 1.4.6, Hume writes that whether or not the relation ofpersonal identity is a "real bond" or "real connection" among perceptions is a "question we might easily decide, ifwe wou'd recollect whathas been already pro^d at large, that the understanding never observes any real connexion among objects, and that even the union of cause and effect, when strictly examin'd, resolves itselfinto a customary association ofideas" (T 259-60). A mere three paragraphs later, Hume writes that "the true idea of the human mind, is to consider it as a system of different perceptions or different existences, which are link'd together by the relation ofcause and effect, and mutually produce, destroy, influence, and modify each other" (T 261). So Hume's view, at 1.4.6, is that personal identity requires causation, but does not require a real connection. It is curious that in the appendix Hume takes the claim Volume XVIII Number 2 219 LOUIS E. LOEB thatthereis noreal connectionbetween perceptions toruinhis account of personal identity, whereas in book 1 he treats this result with equanimity. Thispuzzlecan begeneralized somewhat. Hume observesin 1.3.14 that "the terms of efficacy, agency, power, force, energy, necessity, connexion, andproductive quality, are all nearly synonimous" (T 157). His principal negative claim in that sectionis that(takingefficacy, and the other nearly synonymous concepts, to require something in objects over and above constant conjunction) there is no efficacy, necessity, or connection in causation. Hume targets a number of the nearly synonymous notions not only in 1.3.14, but also at T 246-51 of 1.4.5, and T 632-33 ofthe appendix. In the discussion ofpersonal identity in the appendix, Hume seems to be in search of the sort of bond or connection that he has forcefully rejected, as if he has a lingering commitment to real connections, or to necessity, despite himself. From this perspective, his misgivings easily appear to constitute a retrogression, orlapse, into amode ofthought, or metaphysical picture, that he has taken pains to reject. This is not an attractive explanation ofHume's misgivings. It has the consequence that Hume simply changes his mind, or is of two minds, inregard to therole ofreal connections in an account ofpersonal identity. Although I do not think these possibilities are to be dismissed outofhand, much oftheir support would have to derive from the failure of alternative accounts of what is bothering Hume. At the same time, a solution ought in some way to relate to Hume's thinking about real connections. Hume does write in the appendix, In short there are two principles, which I cannot render consistent; nor is it in my power to...