Almost everyone seems to think that we retain in the mind _only_ those
things that we can voluntarily recall; that memory, in other words, is
limited to the power of voluntary reproduction.

This is a profound error. It is an inexcusable error. The daily papers
are constantly reporting cases of the lapse and restoration of memory
that contain all the elements of underlying truth on this subject.

[Sidenote: _Causes of Forgetfulness_]

It is plain enough that the memory _seems_ decidedly limited in its
scope. This is because our power of voluntary recall is decidedly
limited.

But it does not follow simply because we are without the power to
deliberately recall certain experiences that all mental trace of those
experiences is lost to us.

_Those experiences that we are unable to recall are those that we
disregarded when they occurred because they possessed no special
interest for us. They are there, but no mental associations or
connections with power to awaken them have arisen in consciousness._

[Sidenote: _Seeing with "Half an Eye"_]

Things are continually happening all around us that we see with but
"half an eye." They are in the "fringe" of consciousness, and we
deliberately ignore them. Many more things come to us in the form of
sense-impressions that clamorously assail our sense-organs, but no
effort of the will is needed to ignore them. We are absolutely