an indispensable part of our knowledge of
the past.

The second datum is that we certainly have more capacity for knowing the
past than for knowing the future. We know some things about the future,
for example what eclipses there will be; but this knowledge is a matter
of elaborate calculation and inference, whereas some of our knowledge of
the past comes to us without effort, in the same sort of immediate way
in which we acquire knowledge of occurrences in our present environment.
We might provisionally, though perhaps not quite correctly, define
"memory" as that way of knowing about the past which has no analogue in
our knowledge of the future; such a definition would at least serve to
mark the problem with which we are concerned, though some expectations
may deserve to rank with memory as regards immediacy.

A third point, perhaps not quite so certain as our previous two, is that
the truth of memory cannot be wholly practical, as pragmatists wish
all truth to be. It seems clear that some of the things I remember are
trivial and without any visible importance for the future, but that my
memory is true (or false) in virtue of a past event, not in virtue of
any future consequences of my belief. The definition of truth as the
correspondence between beliefs and facts seems peculiarly evident in the
case of memory, as against not only the pragmatist definition but also
the idealist definition by means of coherence. These considerations,
however, are taking us away from psychology, to which we must now
return.

It is important not to confuse the two forms of memory which Bergson
distinguishes in the second chapter of his "Matter and Memory,"
namely the sort that consists of habit, and the sort that consists of
independent recollection. He gives the instance of learning a lesson
by heart: when I know it by heart I am said to "remember" it, but this
merely means that I have acquired certain habits; on the other hand,
my recollection of (say) the second time I read the lesson while I was
learning it is the recollection of a unique event, which occurred only
once. The recollection of a unique event cannot, so Bergson contends,
be wholly constituted by habit, and is in fact something radically
different from the memory which is habit. The recollection alone is true
memory. This distinction is vital to the understanding of memory. But
it is not so easy to carry out in practice as it is to draw in theory.
Habit is a very intrus