How To Be An Agnostic
body. Within this understanding, it is in the continuity of being
embodied across a lifetime that your personal identity resides. It
is a natural assumption to make, though it runs into problems
because our bodies change over time. Strictly speaking, as our
cells die and are replaced, we actually gain completely new bodies
over time. Given that is the case, the philosopher has to give an
account of how personal identity survives that physical change.
Attempting to do so leads to the second option, that personal
identity is to do with memory or some complex of psycholog-
ical factors. These, apparently, persist in spite of the physical
changes. We can, for example, recount events from our child-
hood, and they are in some way linked to who we have become.
However, the psychological account of identity again falls down
because our memories are fl awed. Radical psychological changes
occur across the course of a life, seemingly disrupting personal
continuity. Indeed, you may not even remember your school-
days, and be grateful for the lapse. But that does not imply they
have ceased to be a part of you.
So both the physical and psychological accounts of personal
continuity run into profound diffi culties. And yet, it is still the
case that human beings have a clear sense of being single indi-
viduals across the course of their lives, for all that they are also
continually in the midst of change. So are there any further
alternatives that might explain this conundrum?
One takes us back to conceptions of the soul. Borrowing
from Aristotle again, it proposes that being the same person
over time rests on what is called our ‘basic being’. In his book
De Anima, or ‘On the Soul’, Aristotle describes our basic being
as ‘that which lies under’ the being of our everyday lives. It is
the ground of our being, or the essence of ourselves. It is the
substance which undergoes all the changes and yet still main-
tains a connection with the past. It may be thought of as like
energy: energy is conserved, modern physics tells us, for all that
it changes from one type to another.
This possibility throws light on the body theory and the psy-
chology theory of personal identity; it could help to highlight