Johann Gottlieb Fichte. Science of Knowledge. Edited and Translated by Peter Heath and John Lachs. New York: Meredith Corporation, 1970.

Johann Gottlieb Fichte’s Foundation of the Complete Science of Knowledge (Grundlage der gesammten Wissenschaftslehre, 1794-95) describes the extent to which consciousness is a self-determining activity. Fichte is concerned with how consciousness determines the self, and with how consciousness is determined by the self. He also explains how consciousness determines the nature of reality.

Fichte claims that there are two possible approaches to philosophy: Idealism or Dogmatic Realism. The aim of Idealism is to gain true and valid knowledge of the self and of how the ideas of the self correspond to reality. The aim of Dogmatic Realism, says Fichte, is to know objects which are assumed to exist independently of experience and which therefore have no reality. Thus, the Science of Knowledge is a form of Transcendental Idealism, which is based on both reason and experience but transcends or goes beyond them.

Fichte agrees with Kant that everything in consciousness is conditioned by self-consciousness. But Fichte says that the content of consciousness is also determined by self-consciousness. Everything in consciousness is determined by whether the self is conscious of itself, or of the not-self.

Fichte explains that the Science of Knowledge begins with the self as a direct intuition, and that it ends with the self as an idea. Neither the self as a direct intution, nor the self as an idea, are concerned with individuality. Fichte says that there is a difference between selfhood and individuality. The concept of selfhood refers to consciousness of what is internal to the self, as contrasted with what is external to the self. The concept of individuality depends on consciousness of what is external to the self, i.e. the difference between the self and other persons or beings.

According to Fichte, the essence of the self consists of its consciousness of itself. Self-consciousness cannot be separated from the existence of the self. If the self is to exist, it must be conscious of itself. The self cannot exist without being conscious of itself. The self is that which is conscious of itself.

Fichte notes that his philosophy of existence differs from that of Descartes, whose famous dictum, "cogito, ergo sum" ("I think, therefore I am") asserted that to think is to exist. Fichte says that thinking is not the essence of existence, but is instead a specific determination of existence. The existence of the self may be determined in other ways which do not depend on whether the self is capable of thinking.

For the self to act, it must be conscious of itself. Fichte says that the Act by which the self becomes conscious of itself is the First, Absolutely Unconditioned Principle of the Science of Knowledge. The Second Principle, Conditioned as to Content, is the Act by which the non-self is opposed to the self. The Third Principle, Conditioned as to Form, is the Act by which the self and the non-self are posited as divisible, so that a limited self may be opposed to a limited non-self. Thus, the Third Principle defines an Act of Knowledge by which the opposed self and non-self may be unified without mutual elimination.

For the self to be conscious of the non-self, the self must already be conscious of itself. Fichte says that insofar as the self is conscious of the non-self, the self is not conscious of itself. The self must divert its consciousness from itself, in order to be conscious of the non-self.

Fichte views the non-self as the negation of the self. The self and the non-self limit each other. The self is conscious of being able to limit the non-self, and is conscious of being limited by the non-self. The limitable self is divisible in its consciousness of itself, unlike the absolute self. The absolute self is absolutely conscious of itself, and nothing limits or opposes its consciousness of itself.

For the self to be conscious that it is limited by the non-self, the self must determine itself. Fichte says that the self is a substance insofar as its existence is determined. However, the self is accidental insofar as its existence is not determined. Thus, the self exists in a realm of both substance and accident.

The self is active insofar as it is conscious of itself, and is passive insofar as it is limited by the non-self. The active self determines itself, while the passive self is determined by the non-self. Fichte says that passivity is a negation of activity, just as the non-self is a negation of the self.

When the self is active, it is conscious of itself as a substance or accident. The non-self is active insofar as the self is passive. Activity in the non-self is determined by passivity in the self. The self is conscious of its own passivity when it is conscious of the non-self’s activity. Passivity in the self and activity in the non-self have a reciprocal relationship.

Fichte asserts that the activity of the self is equivalent to the reality of the self. The reality of the self is its consciousness of itself. The self is real insofar as it is conscious of itself. The non-self is real insofar as the self is conscious of the non-self. Thus, the self is the source of reality, both for itself and for the non-self. The non-self does not have its own reality. The non-self depends for its reality upon whether or not it is posited and determined by the self.

If the self excludes something from its consciousness of itself, then it determines something to exist within an indeterminate totality. If the self does not exclude anything from its consciousness of itself, then the self is conscious of an absolute totality.

The self may determine itself, or may be determined by itself. If the self is determined by itself, then it also determines something beyond itself. The self is conscious of itself as determining itself, and as determining the non-self.

To the extent that the self transfers reality to the non-self, the self may also be determined by the non-self. If the self is conscious of itself as lacking something, then it is conscious of something within the non-self. The self may negate itself by transferring reality to the non-self.

The absolute self is absolutely and infinitely conscious of itself. The absolute self exists absolutely and infinitely through its consciousness of itself. Everything that is posited by the absolute self is posited as self, and the absolute self can posit nothing other than itself.

If the self is absolutely conscious of itself, then its consciousness of itself is complete. If the self is not absolutely conscious of itself, then its consciousness of itself is incomplete and must be completed by the non-self.

The absolute self includes all reality within itself. But the finite self is conscious of being limited by the reality of the non-self. The finite self is also conscious of the existence of an absolute self which is not limited by the non-self.

Reflection of the self upon itself may be interrupted by reflection upon the non-self. The activity of the self is free to reflect upon the self or the non-self. When the self reflects continuously upon itself, it is not limited by the non-self.

Thus, Fichte describes the Science of Knowledge as a form of Transcendental Idealism, which shows that the self is both ideal and real. The ideal activity of the self is that by which the self becomes conscious of itself. The real activity of the self is that by which the self determines itself.