so the mental activity of the second system, which should have at its
disposal all the memories stored up by experiences, would be hindered.
But two ways are now opened: the work of the second system either frees
itself completely from the principle of pain and continues its course,
paying no heed to the painful reminiscence, or it contrives to occupy
the painful memory in such a manner as to preclude the liberation of
pain. We may reject the first possibility, as the principle of pain also
manifests itself as a regulator for the emotional discharge of the
second system; we are, therefore, directed to the second possibility,
namely, that this system occupies a reminiscence in such a manner as to
inhibit its discharge and hence, also, to inhibit the discharge
comparable to a motor innervation for the development of pain. Thus from
two starting points we are led to the hypothesis that occupation through
the second system is at the same time an inhibition for the emotional
discharge, viz. from a consideration of the principle of pain and from
the principle of the smallest expenditure of innervation. Let us,
however, keep to the fact--this is the key to the theory of
repression--that the second system is capable of occupying an idea only
when it is in position to check the development of pain emanating from
it. Whatever withdraws itself from this inhibition also remains
inaccessible for the second system and would soon be abandoned by virtue
of the principle of pain. The inhibition of pain, however, need not be
complete; it must be permitted to begin, as it indicates to the second
system the nature of the memory and possibly its defective adaptation
for the purpose sought by the mind.

The psychic process which is admitted by the first system only I shall
now call the _primary_ process; and the one resulting from the
inhibition of the second system I shall call the _secondary_ process. I
show by another point for what purpose the second system is obliged to