principles we have now exhausted the measure of that which is unconditioned and absolutely certain. We can embrace the three in the following formula: _I posit in the Ego a divisible non Ego over against the divisible Ego._ No philosophy can go beyond this cognition, and every fundamental philosophy should go back to this. Just so far as it does this, it becomes science (_Wissenschaftslehre_). Every thing which can appear in a system of knowledge, as well as a farther division of the Theory of Science itself, must be derived from this. The proposition that the Ego and the non-Ego reciprocally limit each other, may be divided into the following two: (1) the Ego posits itself as limited through the non-Ego (_i. e._ the Ego is in a cognitive (or passive) relation); (2) the Ego posits the non-Ego as limited through the Ego (_i. e._ the Ego is in an active relation). The former proposition is the basis of the theoretical, and the latter of the practical part of the Theory of Science. The latter part cannot, at the outset, be brought upon the stage; for the non-Ego, which should be limited by the acting Ego, does not at the outset exist, and we must wait and see whether it will find, in the theoretical part, a reality. _The groundwork of theoretical knowledge_ advances through an uninterrupted series of antitheses and syntheses. The fundamental synthesis of the theoretical Theory of Science is the proposition: _the Ego posits itself as determined_ (limited) _by the non-Ego_. If we analyze this sentence, we find in it two subordinate sentences which are reciprocally opposite. (1) The non-Ego as active determines the Ego, which thus far is passive; but since all activity must start from the Ego, so (2) the Ego determines itself through an absolute activity. Herein is a contradiction, that the Ego should be at the same time active and passive. Since this contradiction would destroy the above proposition, and also suppress the unity of consciousness, we are forced to seek some point, some new synthesis, in which these given antitheses may be united. This synthesis is attained when we find that the conceptions of action and passion, which are contained under the categories of reality and negation, find their compensation and due adjustment in the conception of divisibility. The propositions: “the Ego determines,” and “the Ego is determined,” are reconciled in the proposition: “the Ego determines itself in part, and is determined in part.” Both, however, should be considered as one and the same. Hence more accurately: as many parts of reality as the Ego posits in itself, so many parts of negation does it posit in the non-Ego; and as many parts of reality as the Ego posits in the non-Ego, so many parts of negation does it posit in itself. This determination is _reciprocal determination_, or _reciprocal action_. Thus Fichte deduces the last of the three categories under Kant’s general category of relation. In a