the difference between the "Ego and the Non-ego,"_ and yet, in
the same breath, annihilates that difference, and proclaims their
"identity."[138] Fichte admits, indeed, that we have the idea of
something which is _not-self_; but instead of ascribing it to an
external object, he accounts for it by a law of our mental nature, which
constrains us to _create a limit_, so as to give a determinate character
to our thought. The three technical formulas, therefore, which are
said[139] to express, respectively,--the affirmation of self,--the
affirmation of not-self,--and the determination of the one by the
other,--are all equally the products of our own mental laws, and do not
necessarily require the supposition of any external object; and hence it
follows that Self is the one only absolute principle, and that
everything else that is conceived of is constructed out of purely
subjective materials. The question whether the "object" be the
generative principle of the "idea," or _vice versa_, is thus superseded;
for there is no longer any distinction between "object" and "subject;"
existence is identified with thought; the _Ego_ and the _Non-ego_ unite
in one absolute existence; and Self becomes the sole Subject-object, the
percipient and the perceived, the knowing and the known.

Of course, on this theory, there is no knowledge of God, just as there
can be no knowledge of Nature, and no knowledge of our fellow-men, as
distinct objective realities; it is a system of pure Idealism, which, if
consistently followed out, must terminate in utter _skepticism_ in
regard to many of the most familiar objects of human knowledge; or,
rather, in the hands of a thoroughly consequent reasoner, it must issue,
as Jacobi endeavored to show, in absolute _Nihilism_; since we can have
no better reason for believing in the existence of Self than we have
for believing in the reality of an external world, and the coexistence
of our fellow-men. Each of these beliefs is equally the spontaneous
product of certain mental laws, which are just as trustworthy, and need
as little to be proved, in the one case as in the other.

Fichte seems to have become aware of this fundamental defect of his
system; and, at a later period, he attempted to give it a firmer basis
by representing _self_, not as individual, but as Divine, that is, as
the Absolute manifesting itself in Man. He now admitted what, if he had
not denied, he had overlooked before, an essential reality as