Version: v3, Published online: 2017
Retrieved October 19, 2018, from https://www.rep.routledge.com/articles/thematic/personal-identity/v-3
2. Psychological Continuity Theories
Locke’s assertion that when sameness of consciousness comes apart from sameness of substance the person goes with the consciousness has a great deal of intuitive appeal There are, however, also some difficult challenges involved in turning this intuition into a developed account of personal identity. One of the most fundamental is that it is not clear exactly what 'sameness of consciousness' consists in. This kind of continuity is usually taken to be essentially bound up with the capacity for remembering past experiences ‘from the inside’, that is, remembering not just that something happened, but recalling what it was like to experience it from the first-person perspective, what it felt and sounded and looked like. Locke's view is interpreted as the claim that someone's ability to remember past experiences makes them the person who had those experiences. There are, however, a host of very serious objections that can be raised against this kind of simple memory theory. It seems to imply, for instance, that if I claim to remember being sworn in as the fifth President of the United States this makes me James Monroe, or that a murderer who forgets his crime is no longer the person who committed it. Because of these and other difficulties, there is general consensus that a straight memory theory of identity is not viable.
The latter half of the twentieth century saw a renewed and focused interest in identity questions in general and questions of personal identity in particular. In this context, several philosophers sought to reclaim Locke’s basic insights and methods and use them to produce a more precise and defensible account of personal identity (For examples and descriptions of this view see e.g. Lewis 1976; Parfit 1984; Perry 1976; Shoemaker 1984; Noonan 1989). The resulting psychological continuity theories define personal identity in terms of overlapping chains of psychological connections (i.e. the connection between a memory and the experience of which it is a memory, between an intention and the action that carries it out, or between different temporal portions of a continuing belief, desire, or trait) that are appropriately caused. As mentioned earlier, these theories are defended using essentially the same methodology Locke used. They also follow Locke in that they are relational rather than substance-based accounts and draw close connections between personal identity and practical concerns. Twentieth-century psychological continuity theories differ from the memory theory attributed to Locke, however, in three significant ways: first, they include psychological connections other than memory; second, they require these connections to be appropriately caused; and third, they require overlapping chains of connections rather than direct connections.
The first difference is in the interest of generally increasing plausibility. Psychological theorists argue that memory is not the only important psychological connection, and so other kinds of connections should be included in an identity criterion. The second change is made to deal with problems of delusional memory-like experiences of the sort described above. Psychological theorists must avoid the consequence that someone who has delusions of having been sworn in as the fifth US President, no matter how sincere, is for that reason identical to Monroe. The most straightforward way to avoid this result is to say that only genuine memories constitute personal identity. The problem with this strategy, however, is that the most obvious way of distinguishing between genuine memories and delusions is by saying that in the former case but not the latter the putative memory is of an experience that the supposed rememberer actually had. The problem is that this approach defines personal identity in terms of genuine memory and genuine memory in terms of personal identity, making the view viciously circular. To avoid this difficulty, psychological theorists use the requirement of appropriate cause to distinguish between delusions and the kinds of memory experiences that actually contribute to identity. Monroe’s memory-like experiences of being sworn in are causally connected to Monroe’s swearing in in a way that the delusional memory-like experiences are not. Psychological theorists call appropriately-caused memory-like experiences 'quasi-memories'. Those who make use of this device point out that someone might in theory have a non-delusional quasi-memory of an experience they did not have (e.g. if neurosurgeons were able to transplant memory traces). This means that quasi-memory does not presuppose identity, allowing a definition of identity in terms of quasi-memory (and quasi-intentions, quasi-beliefs, etc.) to avoid circularity.
The third change is made to avoid problems with transitivity. A man of 40, while taking a vacation, might remember a vacation that he took when he was 20, and a man of 70 might remember the vacation of the man of 40 but have no recollection of the vacation the 20-year-old took. On a straight memory theory, this makes the man of 70 the same person as the man of 40, and the man of 40 the same person as the man of 20. From these facts and the transitivity of identity (if A=B and B=C then A=C) it follows that the man of 70 is the same person as the man of 20. However, since the memory theory says that someone must remember an earlier person's experiences in order to be that person, it also implies that the man of 70 is not the same person as the man of 20. This absurd conclusion can be avoided if identity is defined in terms of overlapping chains of psychological connections rather than only in terms of direct connections. This alteration allows the view to say consistently that the 70-year-old is the same person as the 20-year-old.
These revisions, together with a number of smaller changes, produce the family of psychological continuity theories which have been a dominant feature of the philosophical landscape for some time. .
Schechtman, Marya. Psychological Continuity Theories. Personal identity, 2017, doi:10.4324/9780415249126-V024-3. Routledge Encyclopedia of Philosophy, Taylor and Francis, https://www.rep.routledge.com/articles/thematic/personal-identity/v-3/sections/psychological-continuity-theories.
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