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Chapter 8 Personal Identity | ||
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continued, Section 4 of 4
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Pages: 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 The subject matter of the articles is difficult, but the clarity of the prose is such that readers unfamiliar with the subjects can still work through to the articles' important results. Also, the cited references lead us out to a burgeoning orchard of evidence. Readers unimpressed by the articles themselves would do well to sample the surrounding evidence before moving on. But the time is already ripe for moving on. The cumulative weight of evidence bends us
to the conclusion that subjectivity does indeed have a corporeal basis.[50]
 In
this chapter we have examined the three Great Criteria of personal identity
— memory, continuity and subjectivity — and found each to have a
corporeal basis. These results indicate that personal identity is, as a
whole, corporeal.
We
note in passing that philosophers have proposed a few other conditions of
personal identity.[51]
Most of these conditions are variations on the three themes of this chapter;
hence subject to the same corporeal limitations. So we can proceed without
visiting the alternative definitions.
At this point it might be helpful to
arrange the criteria into some "temporal sequence of emergence," or
"order of creation." The ordering is not critical, so this
argument will be brief. Literally, "1-2-3."
Both
subjectivity and memory require bodily continuity for their function. The
neurons that comprise the working brain must be kept in a healthy state,
continuously, for the duration of life. Damage to the neurons — any break
in their continuity — has a deleterious effect. For example, a
deficiency of potassium impairs nervous transmissions and is experienced as
confusion. So it is almost certain that the onset of continuity must in some way
precede the onset of subjectivity and memory during the emergence of consciousness.
As for subjectivity and memory: subjectivity may be
more robust than memory. The subjective experience can sustain itself in the
event of widespread damage to frontal lobes, as we've noted in Section 3 of this chapter.
More to the point, infants are seen to exhibit subjective
awareness during the period of memory failure known as "infantile
amnesia;"[52] and adults also maintain subjectivity when
injury leaves them unable to acquire long-term memories.[53]
This suggests that the brain can maintain a minimal subjectivity
even when a long-term memory system is absent. So perhaps subjectivity in some
way precedes memory during the emergence of consciousness.
At birth, the
possible order of emergence for personal identity criteria would therefore be:
The order of destruction at death is more
speculative, but conceivably it might be:
We can imagine how the ordering might stage
destruction of personal identity at death; first, by effacing long-term
memories as the surface layers of neocortex shut down; then, as stillness
penetrates the limbic system deeper within, disbanding subjectivity. At
the end, cell death throughout the brain would break the functional continuity
of the nervous system, withdrawing any possibility that the physical structure could reinstate its lost personal identity.
Complete
mortality would seem therefore to nullify personal identity at death.
Where necessary conditions are lacking, personal identity cannot exist.
Neither has this chapter offered up any metaphysical gifts. The corporeal
basis of personal identity would seem to constitute a cul-de-sac for
metaphysical philosophy; just because corporeality, by itself, leads
nowhere. It is a metaphysical dead end.
Or so it may
appear. What the negative judgment overlooks is the fact that this chapter has instead
produced the second key to our metaphysical
lock. The first key we recall as being the natural truth of complete
mortality. And now we have our second key, which is just the
corporeal basis of personal identity. This second natural truth complements the first, and it is
equally important to the thesis.
Now both keys
are in hand. We can open the lock and breach the ebony wall.
next Chapter 9: Existential Passage | ||
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Chapter 8, Section 4 Endnotes |
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[48] Newman, Baars, and Cho 1195-1206.
[49] John G. Taylor, "Neural Networks for
Consciousness" 1207-25.
[50] Some scientific texts exploring conscious life:
[51] I should note that subjectivity lies at the core of
intentionality. Some philosophers consider intentionality to be a criterion of personal identity — where an "intentional stance" is understood
(after Brentano) as "the direction of the mind on an object." Here we see that the distinction between self and object is a requirement of
intentionality. It follows that subjectivity is really the more fundamental criterion.
(This observation is unoriginal. See, for example, Gennaro 107: "[I]ntentional states
(conscious or not) are irreducibly subjective.")
For historical reviews and contemporary explorations
of the proposed criteria of personal identity,
see Perry, Personal Identity; Noonan, Personal Identity.
For an insightful critique of several proposed
criteria, see Shalom, The Body/Mind Conceptual Framework
& The Problem of Personal Identity.
See also, papers on personal identity, organized by David
Chalmers.
[52] Fuster 212-13.
[53] Clinical studies of medical subject H. M. detail a famous real-world
example of perpetual memory loss. For a description of H. M.'s memory deficiency
see Milner, Squire, and Kandel 447-53.
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Copyright © 1999
Wayne Stewart
Last update 4/19/11