d effect, and not others quite
different)? While Kant correctly described these functions of the intuiting
and thinking spirit, and showed them actual, they must further be proven,
be shown necessary or deduced. Deduced whence? From the "deed-acts"
(_Thathandlungen_) of the ego which lie at the basis of all consciousness,
and the highest of which are formulated in three principles.

%(b) The Three Principles.%--At the portal of the Science of Knowledge we
are met not by an assertion, but by a summons--a summons to
self-contemplation. Think anything whatever and observe what thou dost,
and of necessity must do, in thinking. Thou wilt discover that thou dost
never think an object without thinking thyself therewith, that it is
absolutely impossible for thee to abstract from thine ego. And second,
consider what thou dost when thou dost think thine "ego." This means
to affirm or posit one's self, to be a subject-object. The nature of
self-consciousness is the identity of the representing [subject] and
the represented [object]. The pure ego is not a fact, but an original
doing, the act of being for self (_Fuersichsein_), and the (philosophical,
or--as seems to be the case according to some passages--even the common)
consciousness of this doing an intellectual intuition; through this we
become conscious of the deed-act which is ever (though unconsciously)
performing. This is the meaning of the first of the principles: "The _ego_
posits originally and absolutely its own being," or, more briefly: The ego
posits itself; more briefly still: I am. The nature of the ego consists in
positing itself as existing.[1] Since, besides this self-cogitation of
the ego, an op-position is found among the facts of empirical
consciousness (think only of the principle of contradiction), and yet,
besides the ego, there is nothing which could be opposed, we must assume
as a second principle: To the ego there is absolutely opposited
a _non-ego_. These two principles must be united, and this can be
accomplished only by positing the contraries (ego and non-ego), since they
are both in the ego, as reciprocally limiting or partially sublating
one another, that is, each as _divisible_ (capable of quantitative
determination). Accordingly the third principle runs: "The ego opposes in
the ego a divisible non-ego to the divisible ego." From these principles
Fichte deduces the three laws of thought, identity, contradiction, and
sufficient reason, and the three