How to Read the 'Science of Knowledge' (Wissenschaftslehre) Logically

The language of Fichte's 1794 Foundation (Grundlage der gesamten Wissenschaftslehre) is highly idiosyncractic, and there is a strong tendency in the secondary literature to adopt Fichte's terms without further clarification. In this blog post, I want to explain why this is problematic and offer a solution.

The problem with adopting Fichte's language is that his terms, almost without exception, have a strong physical resonance. For example, Fichte describes an "activity of the Self" that "goes out into the infinite", that is "checked", and thereby "reflected backwards". He also describes an "interaction" between the Self and the Not-Self that is governed by the concept of causality, and another type of "interaction" which views the Self as a "substance". This terminology understandably invites one to think that Fichte is indeed talking about the physical concept of causality, where the Self and the Not-Self are billiard balls banging against one another, and the physical concept of substance, where the Self is, say, some amorphous physical substrate. Indeed, Fichte even refers mulitple times to "the entire mechanism of the human mind." The problem with such a physical understanding of these terms is that Fichte's philosophy is, at its very core, directed against a mechanistic, or physical understanding of the human mind. The mind is not a mechanism, but rather a being that trades in concepts. That is a central tenet of Fichte's philosophy.

A correct reading of the Foundation must have an explicit and resolute strategy to explain this physical imagery as mere imagery that is ultimately trying to explain something non-physical. The stragegy must be resolute, because the temptation to let physicality creep into our understanding of the philosophical claims is insidious to the project of transcendental philosophy that Fichte inherits from Kant. For example, Kant appeals to the concept of causality when descriping affectation from a Thing-In-Itself, even though he claims that he is not applying the category of causality. As Jacobi famously pointed out in David Hume über den Glauben, how else is one to understand causality, or affection, if not in its normal, physical sense, where one physical object impinges on another? The transcendental project, as it apples to theoretical philosophy, is to explain the conditions according to which knowledge of the physical world is possible. This is how Kant defines to the project and how Fichte intends to complete it. If we are to explain the conditions of our apprehension of the physical world, and if we are to assert that these conditions are not physical, i.e. knowledge is not a mechanistic affair, then we cannot use physical terms to outline those conditions. Or at least the physical terms we use can only be used in a purely metaphorical sense, and it is then incumbent upon us to make the metaphorical use explicit, to make clear that we are using metaphors, and to attempt to explain the semantic content which these metaphors attempt to capture.

I argue that Fichte, in his definitions of causality and substance, does offer us an alternative, non-physical understanding of these terms. It is these defintions, that, I argue, are the correct way to read him, and that allow us to avoid the temptations of physical language. These definitions define causality and substance in terms of empirically directed propositional logic, in terms of a logic that makes truth-claims about the empirical world.

The logical construal of causality

"Causality" is a kind of "interdetermination" (Wechselbestimmung). Fichte defines interdetermination like so:

By means of the determination of reality or negation of the Self, we determine at the same time negation or reality of the Not-Self; and visa-versa.

Durch die Bestimmung der Realität oder Negation des Ich wird zugleich die Negation oder Realität des Nicht–Ich bestimmt; und umgekehrt.

If we replace "Self" and "Not-Self" with the propositions p and ¬p, then we can see that this is a version of the law of the excluded middle. The "reality", or truth, of p, determines the "negation", or falsity, of ¬p, and visa versa.

We get from a simple proposition p to the topic of the "Self" and "Not-Self" by considering that the "Self" is a rational agent who judges, which among other things, means that the Self makes claims about what is, empirically, the case. Empirical reality can thus be construed as the set of propositions that the Self makes about the empirical world. A certain number of these propositions will be false, since it is inherent in the notion of a rational agent that our judgments about what is the case can err. Thus for any set of n propositions that the self makes S = (p₁, p₂, p₃,..., p_n) there is corresponding set of the contradictory propositions S' = (¬p₁, ¬p₂, ¬p₃,..., ¬p_n). Precisely those propositions will be true in set S that will be false in the contradictory set S', and, visa versa, precisely those prositions will be false in set S that are true in set S'. This is just the law of the excluded middle applied to a set of propositions. The "Self", on this view, is the set of empirical propositions the Self makes, and the "Not-Self" is the set of propositions which negate those empirical propositions. Objective reality is then some combination of those two opposing sets, which is just to say that some of the Self's claims about what is empirically the case will be correct, and others will be incorrect.

Fichte expresses this notion of the "Self" as a set of truth-bearing, empirical propositions by defining "interdetermination" not just in terms of an interplay of reality and negation, but in terms of "degrees of reality", which Fichte describes like so:

Divide, for example, the totality of reality into 10 equal pieces; posit 5 of them in the Self, then 5 pieces of negation are necessarily posited in the Self

Theilet z.B. die Totalität der Realität in 10 gleiche Theile; setzt deren 5 in das Ich; so sind nothwendig 5 Theile der Negation in das Ich gesetzt

According to this logical construal of Fichte's notion of "interdetermination," the "Not-Self" is simply the negation of everything the Self takes to be the case.

Fichte now defines causality by observing that this relationsip between the Self and the Not-Self is asymmetric. Only the Self can judge, only the Self can put forward propositions. The only thing the Not-Self can do is prove those propositions wrong. Thus the Not-Self is the principle of correction, but not a positing agent. The Not-Self is that which corrects the Self's incorrect empirical judgments. The Not-Self is objectivity. It is the corrective to the Self's ability to make incorrect claims about what is the case.

Fichte describes this step from "interdetermination" to "causality" like so:

...in the concept of interdetermination, it was completely indifferent which one of the two opposites is determined by the other, to which one of them we attribute reality, and to which one of them we attribute negation...In the current synthesis, however, the conversion is not indifferent; rather, it is determined to which of the two members of the opposition we attribute reality, and not negation, and to which of the two members we attribute negation, and not reality.

...im Begriffe der Wechselbestimmung war es völlig gleichgültig, welches der beiden entgegengesetzten durch das andere bestimmt wurde: welchem von beiden die Realität, und welchem die Negation zugeschrieben wurde...In der gegenwärtigen Synthesis aber ist die Verwechselung nicht gleichgültig; sondern es ist bestimmt, welchem von den beiden Gliedern des Gegensatzes Realität, und nicht Negation, und welchem Negation, und nicht Realität, zuzuschreiben sey.

We must, as a starting point, attribute reality entirely to the Self, since it is only the Self which can make propositions. Then, in a second step, we can attribute reality to the Not-Self once we see that the Self has made an incorrect claim, put forth an incorrect proposition. The Not-Self is here strictly reactive - it can only negate that which the Self puts forward. In Fichte's terms: "it is determined to which of the two members of the opposition we attribute reality, and not negation...". First, the Self attributes all reality to itself, since only it has the ability to make claims. Then, when a claim the Self makes fails, the Self corrects its claim, negating its previous, incorrect claim, and thereby "positing" negation it itself and reality in the Not-Self.

This is how Fichte expresses this notion of causality, which acknowledges the asymmetry between a judging subject and the empirical world to which such judgments refer:

The Not-Self has, as such, no reality by itself; but it has reality, insofar as the Self suffers...

Das Nicht-Ich hat als solches, an sich keine Realität; aber es hat Realität, insofern das Ich leidet...

All thought, which means, all propositions, true or false, are the work of the Self, the rational agent who judges. Only when the "reality" of a proposition is negated, i.e. when the Self "suffers," does the Not-Self attain reality. When it turns out not that p, but rather ¬p is the case, the Self suffers a failure of its ability to determine what is the case, and the Not-Self asserts its reality as the find word of true. When the Self corrects its incorrect judgment, the Not-Self, understood as the principle of objectivity, the principle of truth as that which is, rather than that which the Self merely takes to the be the case, makes itself felt.

At this point in Fichte's exposition, it is entirely open, how, exactly, this correction of mistaken empirical propositions takes place. Fichte talks of "affection", but "affection" strictly means "suffering" (Leiden), or the "negation" of "reality", and is thus fully compatible with this logical reading we are proposing. Later on, Fichte will consider multiple ways in which this "causal" interaction between the Self and Not-Self, this correction, "negation" of a proposition, "affection" might happen. There are, namely, four different explanations Fichte considers: "qualitative idealism", "quantitative idealism", "qualitative realism", and "quantitative realism". Without going into what these mean, we can say that the 'qualitative realism' position does see the causal relationship as one of efficient causality, where the Self, and its propsitions, are the determinations of the wider nexus of efficient causality that comprises nature. Similarly, the 'quantitative realism' position thinks of the negation of propositions in terms of Kant's inscrutable "transcendental" affectation, which is a "causality" that occurs from outside the Self, so to speak, but is, nevertheless beyond the reach of the natural-physical realm because it is "transcendental" and comes from the so-called Thing-in-Itself.

The beauty, however, of Fichte's logical notion of causality is that it stands outside of any "realist" construal of causality. "Causality" defines a logical concept of propsitions and their correction. At this point, the mechanism of correction could be realist or idealist.¹

The logical construal of substance

Fichte claims that, like his concept of causality, the concept of substance is a kind of "interdetermination", on the grounds that "reality" determines "negation", and visa versa². The connection is, however, tenuous, for he defines his concept of "interdetermination" in reference to the "reality" or "degrees of reality" of the Self and Not-Self. In contrast, the concept of substance deals only with the Self, and not with the Not-Self. Nevertheless, because substance uses the concepts of reality and negation and incorporates the law of the excluded middle, it can be expressed in the terms of propositional logic.

Fichte's defines substance as the "entire, absolutely determined ambit of all realities"³. Fichte also calls this "totality". Whereas interdetermiantion and causality divided one set of propositions from their contradictory propositions, the concept of substance starts with the unity of a proposition p and its negation ¬p. With respect to any proposition p, the total space of possibility is that p is either true or false. Again, this is just the law of the excluded middle: p ∨ ¬p. Since all propositions issue from the Self, the Self is the source of all potential propositions. The act of judgment is then a selection from the set S = (p, ¬p) to just p or ¬p. Fichte calls this act of judgment both an act of reality and negation; 'reality' insofar as the reality of p (or ¬p, as the case may be) is affirmed, and 'negation' insofar as a judgment is a subset of all possible judgments, so that all judgments that contradict the judgment p (or the judgment ¬p, if that's the judgment) are thereby negated.

"Substance" as "interdetermination" is judgment, where judgment is seen as a selection from all possible propositions. Thus, if we have the contrary propositions p and q, all possible judgments are p, ¬p, q, and ¬q. In the act of judging p, I thereby affirm the judgments p and ¬q, and exclude the contradictory judgment ¬p and the contrary judgment q. In Fichte's terms:

We have now found an X that is at the same time reality and negation, activity and suffering.

a. X is activity, insofar as it relates to the Not-Self, because it is posited in the Self, and in the positing, acting Self.

b. X is suffering, insofar as it relates to the totality of action. It is not action in general, but rather it is a determinate action: one way of acting from among the sphere of action in general.

Es ist jetzt ein X aufgezeigt worden, welches Realität und Negation, Thätigkeit und Leiden zugleich ist.

a. X ist Thätigkeit, insofern es auf das Nicht-Ich bezogen wird, weil es gesetzt ist in das Ich, und in das setzende, handelnde Ich.

b. X ist Leiden, insofern es auf die Totalität des Handelns bezogen wird. Es ist nicht das Handeln überhaupt, sondern es ist ein bestimmtes Handeln: eine unter der Sphäre des Handelns überhaupt enthaltene besondere Handelsweise.

Empirical judgment, the act of judging p about the world, is an activity of the Self. The Self determines the world, the Not-Self, to be p. In this sense, the Self confers reality to p. At the same time, the Self, by committing to p, thereby excludes any contrary judgments, thus limiting itself from a sphere of all possible propositions (Fichte's "totality of action", "action in general") to that proposition it has chosen and any other propositions that are not contrary to that chosen proposition.

As with his concept of causality, Fichte's logical concept of substance is agnostic with respect to idealism or realism. There is an idealist construal of substance that Fichte works out, whereby the totality of possible judgments is present to the Self through its capacity of imagination. The imagination has the ability to contemplate counterfactuals, even in the face of determinate judgments about what is the case. And indeed, Fichte's claim that the Self, and not the Not-Self, is a "substance" shows that, in the end, he favors this idealist construal of substance. Likewise, the idealist construal of substance understands a judgment to be a determination of reality, as the above quote indicates ("X is an activity...because it is posited in the Self..."). However, later, in the his Synthesis of substance in §4.E, Fichte also works out a realist construal of substance, whereby the "undetermined sphere" refers to the world, as yet to be determined, and the act of making a judgment about the world is an act that the world determines, or guides. The details of these accounts, however, are out of the scope of this discussion, but sketched out in a previous blog post on Fichte's system.