Version: v2, Published online: 2011
Retrieved August 16, 2017, from https://www.rep.routledge.com/articles/thematic/personal-identity/v-2
1. Sameness-of-soul views
One approach to the problem of personal identity sees persons as simple, immaterial substances, or souls, and defines personal identity in terms of the persistence of a single soul. This kind of account provides a definitive and straightforward answer to the problem of personal identity and has the advantage of providing true persistence in the form of an unchanging entity. It is, however, widely considered to be untenable in the end. There are several reasons for this. Some question the very coherence of the notion of an immaterial substance, while others who accept the coherence of souls argue that we nevertheless have no reason to believe that such things exist.
The most compelling objection to sameness-of-soul views is the observation that if personal identity is defined in terms of sameness of soul we are never in a position to say when we are dealing with the same person at two different times, even in the case of ourselves. Souls are, by definition, featureless substrata, not detectable by the senses. When I meet my friend Mary under ordinary circumstances and see that she is the same human I always knew as Mary, with the same memories, traits, and so on, I still know nothing about whether the soul I encounter is the same soul I interacted with when Mary and I last spoke and so, on the sameness-of-soul view, I have no evidence that this is really Mary. There is no way to rule out the possibility that the original soul has been replaced by one that is numerically distinct but has been implanted with all the memories the old soul. Similarly, when I wake up in the morning and turn my attention to the tasks I set for myself before going to bed, I cannot be certain that the soul remembering and turning to those tasks now is the same soul that set them before going to bed, rather than another soul to whom the memories have been transferred. Since souls are undetectable, we can have no direct evidence of their persistence.
The considerations described here are epistemological. The concern is that if we were to define personal identity in terms of sameness of soul we would never be in a position to know when we have the same person. This does not rule out the logical possibility that sameness of soul might actually constitute sameness of person, but when the disconnection between the metaphysical and epistemological questions is as complete as it is in this view we are left with no way of defending the metaphysical claim. If we can never know when we have the same immaterial substance we have no basis on which to argue that such sameness constitutes sameness of person - what could be the evidence for such a claim? At the very least this consequence shows that sameness of soul cannot be what we are tracking in our ordinary judgements of personal identity. A criterion of personal identity that has the consequence that we can in principle never know when we are dealing with the same person is not plausible as an account of what we call persons.
Schechtman, Marya. Sameness-of-soul views. Personal identity, 2011, doi:10.4324/9780415249126-V024-2. Routledge Encyclopedia of Philosophy, Taylor and Francis, https://www.rep.routledge.com/articles/thematic/personal-identity/v-2/sections/sameness-of-soul-views.
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