This, then, is the thesis at the very foundation of all _Wissenschaft_: and therefore figures at the head of the _Wissenschaftslehre_,--the name Fichte gives his fundamental philosophy. But alone it is powerless. A foundation is only a foundation, by being built upon. The position must be defined by counterposition: thesis by antithesis: ego by non-ego. Ego, in fact, is first made _such_, as set against _you._ In other words, the perception we assumed to start with does not merely _suppose_ and indeed pre-suppose the absolute Ego; but it sets in the absolute Ego an ego and a non-ego,--sets against the lesser ego, something limiting and limited, something defining it in one particular direction; or, if the original consciousness we started to examine was an act of will, then, it may be said, the non-ego appears as about to be limited and defined by the Ego. Be our consciousness, therefore, practical or theoretical, of action or of knowledge, its fundamental characteristic is the conjunction (correlation with subjugation) of an ego and a non-ego. It is always a synthesis of an original antithesis[5]; of self and not-self. But every such synthesis which brings together into one a self and a not-self, is possible only in the original thesis of a greater self--an absolute Ego--which includes the not-self and the self it contrasts within its larger self. The unity of the first principle[6] (A = A, or I = I) parting or distinguishing itself into the opposition of A versus not-A, Ego set against non-ego, re-asserts itself again in consciousness (perception of objects, and action upon them by will) as synthesis, i. e. a conjunction (not a real union). And this synthesis is either the limitation of the Ego by the non-ego or the limitation of the non-ego by the Ego. The former gives the formula of theoretical, the latter that of practical consciousness. We begin with the absolute Ego. It is absolute activity, utter freedom. It is the source of all action, all life. Yet if thus implicitly everything, it is actually nothing. To be something, it must restrict itself, set up in itself an antithesis:--by the setting up of a not-self, at once limit and realise itself: translate itself from ideal absoluteness and unconditionality into a reality which is also limited and partial. All consciousness and action exhibit this antithesis of a limited self and an outside and adversative other-being; but the antithesis rests upon the medium of a larger life, a thesis which transcends and includes the antithesis, and which leads to that alternating adaptation of the two sides to one another (their synthesis) which actual experience presents as its recurring phase[7]. The _Wissenschaftslehre_ leaving the absolute Ego in the background deals with the play that goes on in human experience between the correlatives to which it has reduced itself;--the antagonism, but the moderated and overruled antagonism, of Ego and non-ego.