Hume's Psychology of Identity Ascriptions

Hume Studies Volume XXII, Number 2, November 1996, pp. 273-298 Hume's Psychology of Identity Ascriptions ABRAHAM SESSHU ROTH Introduction Hume observes that we naturally believe ordinary objects to persist through time and change. The question that interests him in the Treatise1 is, What causes such a belief to arise in the human mind? Hume's question is, of course, the naturalistic one we would expect given that the project of the Treatise is the construction of a "science of man." This paper seeks to clarify Hume's discussion of how we acquire the notion of persisting objects. In the first section, I note that several observations Hume makes about the actions of the mind may all come under the heading of "seeing successions as simple." These observations pose a problem for Hume's system, revealing a tension between his accounts of our ideas of time and persistence: if (as Hume believes) only successions, which are not simple, endure through time, how is it that bodies seen as simple are nevertheless thought to endure or have duration as well? In the second section I show how Hume answers this question. The third section is devoted to an interpretation of Hume's notions of the identity relation and what he calls an "object existent at a time." Identity through time is standardly treated in contemporary analytic philosophy using the notion of a unity relation connecting various temporal parts or stages of a persisting object. One interpretation of Hume takes his talk of the identity relation as signifying just such a unity relation, and "object existent at a time" as referring to a temporal part of an object. Another interpretation makes use of the notion of substance Abraham Sesshu Roth is at the Department of Philosophy, Brandeis University, Waltham MA 02254-9110 USA. Email: philosophia@binah.brandeis.edu 274 Abraham Sesshu Roth and of qualities inhering in a substance at different times. These interpretations concentrate upon metaphysical issues, and neglect the psychological aspects of Hume's discussion of identity. I demonstrate that these interpretations are unacceptable because they cannot be reconciled with Hume's psychologically significant distinction between vulgar or commonplace views on the one hand, and those views held by philosophers on the other. Finally, I propose and defend an alternative view of Hume's account of identity. This new understanding makes use of the notion of distinctions of reason to interpret Hume's idea of an object existent at a time. It turns out that a focus upon Hume's psychology of identity ascriptions will allow us to discern an interesting metaphysical alternative to the temporal parts view of identity. 1. Seeing Successions as Simples There has been some dispute in the literature about the temporal nature of Humean impressions. According to Barry Stroud, Hume holds that if one stares at an unchanging object (in unchanging conditions) for some more than minimal amount of time, one's experience takes the form of a sequence of qualitatively identical impressions, each of which occupies a temporal minimum.2 Thus when I fix my gaze upon an object, I am subject to a temporal series of impressions which may be represented as follows: (1) A A A A Eli Hirsch and Don Baxter question Stroud's assumption that a Humean perception occupies only a temporal minimum.3 Baxter holds that in Hume's view an impression will last as long as you keep looking and the conditions under which you look remain unchanged. So to stare fixedly at an object would on his view be represented in this way: (I') A I side with Baxter and Hirsch on this matter.4 But the dispute in any case has minimal ramifications for the purposes of this paper. My concern is with how Hume thinks a sequence or succession of impressions such as (1) would normally be experienced, i.e., with what idea the common person would derive from such a succession, and with how such an individual would characterize this succession. According to Hume, regardless of whether or not perceptions are extended, if a perceiver were to be presented with a succession like (1), it would be experienced or taken as (V). Hume...