c phenomena which constitute the unity of one "experience," and
transform mere occurrences into "experiences." I have already dwelt upon
the importance of mnemic phenomena for psychology, and shall not
enlarge upon them now, beyond observing that they are what transforms a
biography (in our technical sense) into a life. It is they that give the
continuity of a "person" or a "mind." But there is no reason to suppose
that mnemic phenomena are associated with biographies except in the case
of animals and plants.

Our two-fold classification of particulars gives rise to the dualism of
body and biography in regard to everything in the universe, and not only
in regard to living things. This arises as follows. Every particular of
the sort considered by physics is a member of two groups (1) The group
of particulars constituting the other aspects of the same physical
object; (2) The group of particulars that have direct time-relations to
the given particular.

Each of these is associated with a place. When I look at a star, my
sensation is (1) A member of the group of particulars which is the star,
and which is associated with the place where the star is; (2) A
member of the group of particulars which is my biography, and which is
associated with the place where I am.*

*I have explained elsewhere the manner in which space is
constructed on this theory, and in which the position of a
perspective is brought into relation with the position of a
physical object ("Our Knowledge of the External World,"
Lecture III, pp. 90, 91).

The result is that every particular of the kind relevant to physics is
associated with TWO places; e.g. my sensation of the star is associated
with the place where I am and with the place where the star is. This
dualism has nothing to do with any "mind" that I may be supposed to
possess; it exists in exactly the same sense if I am replaced by a
photographic plate. We may call the two places the active and passive
places respectively.* Thus in the case of a perception or photograph
of a star, the active place is the place where the star is, while the
passive place is the place where the percipient or photographic plate
is.

* I use these as mere names; I do not want to introduce any
notion of "activity."

We can thus, without departing from physics, collect together all the
particulars actively at a given place, or all the particulars passively
at a given place. In ou