THE TWO FACTORS IN IMAGINATION.--From the simple facts which we have
just been considering, the conclusion is plain that our power of
imagination depends on two factors; namely, (1) _the materials available
in the form of usable images capable of recall_, and (2) _our
constructive ability_, or the power to group these images into new
_wholes, the process being guided by some purpose or end_. Without this
last provision, the products of our imagination are daydreams with their
"castles in Spain," which may be pleasing and proper enough on
occasions, but which as an habitual mode of thought are extremely
dangerous.

IMAGINATION LIMITED BY STOCK OF IMAGES.--That the mind is limited in its
imagination by its stock of images may be seen from a simple
illustration: Suppose that you own a building made of brick, but that
you find the old one no longer adequate for your needs, and so purpose
to build a new one; and suppose, further, that you have no material for
your new building except that contained in the old structure. It is
evident that you will be limited in constructing your new building by
the material which was in the old. You may be able to build the new
structure in any one of a multitude of different forms or styles of
architecture, so far as the material at hand will lend itself to that
style of building, and providing, further, that you are able to make
the plans. But you will always be limited finally by the character and
amount of material obtainable from the old structure. So with the mind.
The old building is your past experience, and the separate bricks are
the images out of which you must build your new structure through the
imagination. Here, as before, nothing can enter which was not already on
hand. Nothing goes into the new structure so far as its constructive
material is concerned except images, and there is nowhere to get images
but from the results of our past experience.

LIMITED ALSO BY OUR CONSTRUCTIVE ABILITY.--But not only is our
imaginative output limited by the _amount_ of material in the way of
images which we have at our command, but also and perhaps not less by
our _constructive ability_. Many persons might own the old pile of
bricks fully adequate for the new structure, and then fail to get the
new because they were unable to construct it. So, many who have had a
rich and varied experience in many lines are yet unable to muster their
images of these experiences in such a way that new produ