Personal Identity, Numerical and Qualitative

In the analytic tradition, "the problem of personal
identity" is usually taken to mean a question of numerical
identity over time: what makes X at one time the same
person as Y at another? But the title also fits a set of
questions - at least as interesting - which concern what
may be called qualitative identity. A person"s qualitative
identity comprises his defining properties (DPs): these are
properties that he must mention in a full answer to the
question "Who am I?", taken in a special sense which can
be discerned by contrast with the ordinary sense of the
third-person "Who is X?" If you and I are watching a
ceremony and I, pointing to one of the participants, ask
"Who is she?", my purpose is likely to be to find out that
person"s role in the ceremony: the question and the
appropriate answer are relative to my purpose, which is set
by the context. In the sense relevant to DPs, "Who am I?"
is not thus relative to context and purpose: rather, in
answering the question I identify properties of mine that
determine my purposes. There is, however, no simple
asymmetry between the first-person and the third-person
questions; the third-person question can, although it rarely
does, take this sense, and conversely the first-person
question can be relative to purpose and context, as for
example where roles in a game are being assigned and
one of the players is unsure of his role. Nevertheless the
special sense is more prominent in the first-person case.