just now upon a full analysis of what this reference to
a particular region of the past means, I may observe that it takes place
by help of an habitual retracing of the past, or certain portions of it,
that is to say, a regressive movement of the imagination along the lines
of our actual experience. Setting out from the present moment, I can
move regressively to the preceding state of consciousness, to the
penultimate, and so on. The fact that each distinct mental state is
continuous with the preceding and the succeeding, and in a certain sense
overlaps these, makes any portion of our experience essentially a
succession of states of consciousness, involving some rudimentary idea
of time. And thus, whether I anticipate a future event or recall a past
one, my imagination, setting out from the present moment, constructs a
sequence of experiences of which the one particularly dwelt on is the
other term or boundary. And our idea of the position of this last in
time, like that of an object in space, is one of a relation to our
present position, and is determined by the length of the sequence of
experiences thus run over by the imagination.[115] It may be added that
since the imagination can much more easily follow the actual order of
experience than conceive it as reversed, the retrospective act of memory
naturally tends to complete itself by a return movement forwards from
the remembered event to the present moment.

In practice this detailed retracing of successive moments of mental life
is confined to very recent experiences. If I try to localize in time a
remote event, I am content with placing it in relation to a series of
prominent events or landmarks which serves me as a rough scheme of the
past. The formation of such a mnemonic framework is largely due to the
needs of social converse, which proceeds by help of a common standard of
reference. This standard is supplied by those objective, that is to say,
commonly experienced regularities of succession which constitute the
natural and artificial divisions of the years, seasons, months, weeks,
etc. The habit of recurring to these fixed divisional points of the past
renders a return of imagination to any one of them more and more easy. A
man has a definite idea of "a year ago" which the child wants, just
because he has had so frequently to execute that vague regressive
movement by which the idea arises. And though, as our actual point in
time moves forward, the relative pos