In
philosophy,
identity, from ("sameness"), is the relation each thing bears just to itself. The notion of identity gives rise to
many philosophical problems, including the
identity of indiscernibles (if
x and
y share all their properties, are they one and the same thing?), and questions about
change and
personal identity over time (what has to be the case for a person
x at one time and a person
y at a later time to be one and the same person?).