Abstract

In this article, I argue that Fichte's concept of the Anstoß (commonly translated as the 'check') from his 1794 Foundation of the Entire Wissenschaftslehre cannot refer to anything remotely resembling a physical event in Time and Space. This follows from Jacobi's critique of Kant's notion of 'sensibility', from which Fichte concludes that philosophy must provide an exclusively conceptual, rather than realist or naturalist account of thinking. This article offers an alternative account of the Anstoß that is resolutely conceptual. On this account, the Anstoß, properly understood, refers to the logical role that negation plays in the constitution of a thought.

1. Introduction

Fichte's concept of the Anstoß, the check that we, beings who 'posit', encounter in our journey "out into the infinite", has its origins in a language game started by Kant, a game we might call the Freedom Game.¹ Humans, says Kant, are free, free to act, free to think. Kant calls our freedom to think the "spontaneity of thought", and this part of the Freedom Game would be won, if it wasn't for that pesky thing we call reality, or, in Kant's jargon, 'experience' (Erfahrung).² Just because I think about a sumptuous feast laid out before me, doesn't make it so. For that, we would require Aladdin's genie. Kant's next move in this game is to say that our (free) thoughts only have objective validity because of sensibility. "Sensibility", one might think, refers to the way that experience, reality, impinges on our organs of perception, causing us to say 'There is a feast in front of me' if and only if that is the case. But such an understanding of sensibility would end the Freedom Game, for it would mean that our thoughts are not, in fact, free at all, but rather the final expression of sense data coursing through our mind. To keep the game going, Kant paints a picture of what sensibility, in fact, is. It is not impacts from the environment, for those we could characterize as instances of causality. Rather, sensibility happens when "we are affected by objects" (KrV A19/B33; Smith 65). 'Causality', Kant tells us, refers to causal impacts in the physical world, whereas 'affection' and 'sensibility' refer to no such thing.

Jacobi famously pointed out in his 1787 essay On Transcendental Idealism that this move in the Freedom Game was a cheat: "For the word sensibility is without any meaning when we don't understand it as referring to a distinct real medium between one real thing and another, an actual means from some thing to another" (Jacobi 2025: 109; my translation). Arguing that something like 'sensibility' is a 'condition for the possibility of experience' is a fine move to make, as long as it's clear what that something is.³ For example, it is fine to argue that the unity of apperception is a condition for the possibility of thinking, since it is clear what we mean with the words 'I think' when we say 'I think the sky is blue.' It is, however, not okay to use this style of argument to deduce occult phenomenon such as a non-causal "affection". 'Affection', or 'sensibility' is either the causal impact of the world impinging on the mind, or it is nothing at all. But faced with such a clear choice, Kant's system becomes untenable, for it makes an illicit appeal to a special kind of causality, contrived so as not to impinge on the freedom of thought. Once we exclude the possibility of this exotic species of causality known as 'transcendental' affection, we are left with the non-freedom-like claim that the mind, in being "affected by objects," is itself just your garden-variety physical object embedded in the cosmic web of causal relations. In Jacobi's words: "...it drove me perpetually mad that, without this assumption [of the concept of sensibility], I couldn't enter the system, and, with this assumption, I couldn't stay in it" (Jacobi 2025: 109; my translation).

If one is to believe some modern commentators, Fichte's concept of the Anstoß, as introduced in his 1794 Foundation of the Entire Wissenschaftslehre, is intended to address the problem with sensibility: "Fichte invokes the notion of an Anstoß in order to...give an account of what Kant called the "matter of sensation" (Neuhouser 1990: 48). Thus it seems Fichte is saying something like: objects don't 'affect' us, they 'shove' us (sie stoßen uns an). Lest you think that this seems to just rub salt in the wound, then please consider that Anstoß is a term of art, corresponding to no definition in the German language that has anything to do with pushing, shoving, hitting, clinking, etc: "The matter of sensation is explained here...by the inert, wholly passive Anstoß" (Neuhouser 1990: 48). Other commentators are similarly circumspect: "The 'I' is not limited in its judgings/positings by the mere occurrence (or Anstoss) of some nonconceptual content" (Pippin 2000: 157). Whatever the Anstoß is, we know what it is not, namely, neither active nor conceptual. Another commentator says that the "Anstöße" (this plural usage of Anstoß occurs nowhere in Fichte's oeuvre) are "'checks' or 'stimuli'...experiential data whose status is not posited by us." (Pinkard 2002: 117) Thus, perhaps the Anstoß is, after all, active, insofar as it 'stimulates' us, but it is certainly not 'posited'. All of these explanations of the Anstoß fail for the same reason: some way or another they make an illicit appeal to non-conceptual, physical interactions of the mind with its environment.

Fichte, meanwhile, is very clear that there is nothing in experience, nothing at all, unless we posit it. Thus there can be no Anstoß, no "matter of sensation", no "stimuli", no "nonconceptual content" once we, in the words of Wilfrid Sellars, "kill..the Myth of the Given" (Sellars 1963: 195) and thereby accept Fichte's premise that everything must be posited if it can be said to be at all. Thinking is spontaneous through and through. To think otherwise is, as Fichte says, to:

posit our own I outside ourselves, as a thing that exists without any assistance from us — though who knows how. And now, without any assistance from us, some other thing is supposed to have an effect upon this I, just as a magnet, for example, has an effect upon a piece of iron. (GA I/2: 336; Fichte 2022: 265)

Fichte clearly follows the strict either/or of the Freedom Game that Jacobi is insisting on: either you are an 'I' that freely trades in concepts, or you are a physical thing, a "magnet", a "piece of lava in the moon", or what have you, that exists in the nexus of efficient causes (GA I/2: 336; Fichte 2022: 265). It cannot be, as the commentators above would have it, that Fichte is simply doubling down on Kant's illicit appeal to causality, replacing a familiar term like "sensibility" with the obscure neologism 'Anstoß' so as to surreptitiously help himself to all the physicalist imagery he needs.

But what, then, is Fichte's move in the Freedom Game when he invokes the Anstoß? I propose that the only plausible interpretation of the Anstoß is a conceptual interpretation. On this line of argument, the Anstoß refers to the negation of a thought, and everything that the negation of thought brings with it. To negate a thought is to dispute a claim, to object to someone's claim that things are thus and so. This is, after all, how Fichte first uses the term in the 1794 Foundation. Fichte first invokes the term not as a term of art, but rather in the everyday sense of objecting to something (Anstoß nehmen), being shocked or offended by something. Fichte says that "common sense" (der gemeine Menschenverstand) might "object" (Anstoß nehmen) to a claim he has put forth (GA I/2: 331). The claim Fichte is referring to is, for our current purposes, entirely irrelevant (but if you have to know, it's the claim that "real opposition and ideal opposition are the same" (GA I/2: 331)). The only point that needs to be made here is that Fichte's very first employment of the term Anstoß draws a line in the sand between, on the one hand, the conceptual meaning of Anstoß in the sense of an objection or offence, and, on the other, the physical meaning of Anstoß in the sense of pushing, shoving, impacting, etc. I am going to argue in this paper that Fichte's position is emphatically on the conceptual side of this distinction.⁴ Fichte does cross over into the physical realm when he suggests a 'realist' meaning of the Anstoß, but he does so only so that he can reject it and effect a paradigm shift away from Kantian sensibility entirely, and into the realm of the purely conceptual. In this new realm, I argue, the Anstoß refers to negation as a logical feature of thinking, as a logical implication concerning that which one excludes when one makes a claim about things being the case. Fichte's argument is that thought's apparent freedom is simply thought's ability to think what is not.

The interpretative journey we are about to embark on stays exclusively within the confines of Part I and Part II of the Foundation. It makes no appeal to Part III of the Foundation, the Foundation of the Science of the Practical, which was written after the completion of the first two parts. As such, this interpretation stands in opposition to a tendency in the extant literature to explain Fichte's Anstoß with reference to his practical philosophy.⁵ Likewise, the conceptualist interpretation presented here avoids as best it can any appeal to moral concepts, like, for example the 'normative' nature of thinking. It might turn out that the freedom of thought and the possibility of an Anstoß ultimately rest on moral grounds, as Fichte indicates when he says that "it is the practical power that first makes possible the theoretical power" (GA I/2: 286; Fichte 2022: 265). Fichte indeed has interesting things to say about the Anstoß in Part III of the Foundation. However, the longer we can defer in our explanation of the Anstoß a tempting appeal to moral connotations like 'normative' commitment, and the longer we can bracket out Fichte's practical philosophy, the better justice we can do to Fichte's decision to introduce the concept of the Anstoß in the context of theoretical, rather than practical, philosophy.⁶

2. Eliminating Sensibility

Having opened with the claim that Fichte is referring to something entirely conceptual when he talks of an Anstoß, we must now contend with a complicating fact. Fichte's first deliberate employment of the term as a philosophical term of art conceives of the Anstoß entirely in physical, or as he says 'realist', terms. Understanding how and why Fichte employs the term Anstoß here means coming to terms with his unwieldy bestiary of philosophical jargon. The general point is that Fichte employs the term in a last ditch effort to preserve a modicum of naturalism in his account of knowledge. It's the final step in a reductio ad absurdum, which says that try as you might to narrow down the scope of physical determination in an account of knowledge, you will always end up with the absurd claim that thinking is something physical. Fichte calls this absurdity "the error of all realism" which "treats the I purely as a Not-I" and therefore "is unable to explain what is supposed to be explained: the transition from the Not-I to the I" (GA I/2: 355; Fichte 2022: 293).

Fichte presents three versions of 'realism' which progressively zero in on the absurdity of confusing things in the physical world with thoughts. The first he calls 'dogmatic realism' and equates with Spinoza's materialism. Spinoza's materialism, he says, is the most respectable of all the philosophical positions he considers, save his own.⁷ It avoids the absurdity of mixing thoughts with things by simply denying that there is anything like free thought. Thinking, on this view, is merely a reflection of physical processes. However, Fichte finds such a starting position unacceptable because it denies the very freedom of thought, Kant's 'spontaneity of thought', that he is out to defend.

The second version of realism Fichte calls 'quantitative realism' and it is Kant's theory of sensibility. Fichte, at times, has difficulty admitting that this theory is wrong, because, according to Fichte, Kant could do no wrong, and insofar as Kant did botch his theory of knowledge, it was only because Kant "knew very well what he did not say" (GA I/2: 335; Fichte 2022: 273). Nevertheless, we can say that the theory of quantitative realism, Kant's theory of sensibility, is committed to a limited version of physical determination. One has to bite Jacobi's bullet and clear up Kant's shadowy concept of "affection" if one wants to talk at all about Kant's theory of knowledge. Fichte's way of talking about it is to say that, yes, my thoughts are free, but some of them, a certain 'quantity' of them, are wrong. That is the 'quantitative' part in 'quantitative realism'. The 'realism' part of this theory is murky, but it rests on the idea of an external 'determination' or 'affection' that imposes some limits on my thinking.⁸ Fichte summarizes the position by saying "the quantitative realist asserts the reality, independent of the I, of a mere determination" (GA I/2: 334; my translation). Fichte tells us that "It should be immediately obvious to everyone that such a realism is the same as what was established above as Critical Idealism, just as it should also be obvious that Kant established nothing else but this..."(GA I/2: 355; Fichte 2022: 293). If Fichte would indulge us by allowing us to state the obvious, the idea is that, in contrast to the Spinozist, who thinks that the mind is just a reflection of physical processes, the Kantian thinks that thoughts are almost entirely thoughts, endowed as such with the freedom characteristic of thought, but they are also 'determined' in some way that allows us to distinguish correct thoughts from incorrect ones. This 'determination' is 'mere determination' because the manifold of sensibility that allows us to confirm the objective validity of our thoughts is, by itself, no thought at all. However, in its cooperation with thinking, this manifold of sensibility provides just enough of a 'determination' to allow me to ascertain which of my thoughts are true, and which are not.

Fichte sees, in this second version of realism, what Jacobi sees - that this notion of some external 'determination' of thought is incoherent, so long as one is committed to the premise that thinking is free. Fichte is committed to the premise that thinking is free, and so, the next and final move of realism is to say that there is something out there guiding thought in some way towards reality and away from delusion, but we can't really say anything more than that. This move in the language game consists in pointing to some external limitation, something less than an 'affection' or 'determination' and saying 'About that thing, over there, we can say nothing, other than that it's there'. Fichte's loss for words is apparent, and it is in this moment that he grasps, for the first time, at the technical term Anstoß: "all that needs to be present for the I is — if I may express myself in this way — a check...[Anstoß]" (GA I/2: 355–6; Fichte 2022: 292). From here onward, the circumlocutions for — if we may express ourselves this way — that thing, that event over there, start piling up. The Anstoß is the "impossibility of further extension" (GA I/2: 355; Fichte 2022: 292). In fact, the event that we are describing, about which we can say almost nothing "would not limit the I, qua active" (GA I/2: 355; Fichte 2022: 292). Therefore, to quote one of our recent Fichte commentators mentioned in the introduction, the Anstoß must be "inert, wholly passive" (Neuhouser 1990: 48). But that can't be right, because in the same breath in which Fichte claims that this limiting event is not active, he says this: "it would not limit the I, qua active; instead, it would assign it the task of limiting itself." (GA I/2: 355; Fichte 2022: 292). Fichte is allegedly proposing here a "realism that is much more abstract than any of those considered hitherto" (GA I/2: 355; Fichte 2022: 292). But, by invoking the notion of a 'task' (Aufgabe) that the Anstoss 'gives' to the I, he is failing to keep up the game. No merely physical object in the world could possibly 'assign a task' to anybody. An Anstoß that 'assigns a task' is what Fichte would later, in his 1795 Foundation of Natural Right, call a 'summons' (Aufforderung), and only a person, a 'rational being' (Vernunftwesen) can do that.⁹ Fichte claims here that he is presenting a realist theory of the Anstoß, but in fact he is already straddling the divide between the physical and the conceptual. Saying something about nothing is a hard act to keep up.

The New Paradigm

Once one eliminates sensibility, there is only spontaneity, properly understood. Having brought realism to silence, Fichte, in the final 'synthesis', the final argument of §4.E of the Foundation now needs to voice his true position. This is done easily enough: "no infinity, no limitation; no limitation, no infinity" (GA I/2: 358; Fichte 2022: 296). The Anstoß is the limitation that is constitutive of the I's infinitude. Fichte attempts to clarify what he means by pulling these moments apart, imagining that first one thing happens (infinitude), and then the other (Anstoß): "A check happens to the infinitely outgoing activity of the I, an activity within which, precisely because it extends into the infinite, nothing can be distinguished" (GA I/2: 369; Fichte 2022: 306).

Fichte is doing something here similar to what Kant does when he constructs the thought experiment of an 'intuitive understanding', "a divine understanding which should not represent to itself given objects, but through whose representation the objects should themselves be given or produced " (KrV B145; Smith 161). 'Positing' without negation is precisely such a divine act. Anything I think would, by the power of thought alone, be given in experience. Any claim I could possibly make about what exists would, by the power of the claim itself, be true. There is, however, a catch. Such a "divine understanding" would not be able to employ negation. It would be forbidden, or unable, to think what is not. To see why, consider what would happen if it proposed that Aladdin's feast does not exist. The thought alone determines what is given in experience. Namely: Aladdin's feast doesn't exist. However, in making such a proposal, the divine understanding would have 'represented' the (non-existent) feast as that which it is denying exists. Therefore, it would have represented an object (the feast) without producing it. Therefore it wouldn't be a divine understanding.

As Fichte sees it, the thought experiment of a divine understanding has an air of paradox. When we eliminate negation from thought, we arrive at something that doesn't look like thought at all. It looks, instead, like oblivion. For, unable to think what is not, we lose any ability to hold up one object against another and claim that this grape, here, is not the same as that banana, there. The result is that, in the unchecked act of proposing things into existence, we find, as Fichte says, that "nothing can be distinguished." In trying to reach past negation into a realm where everything that is proposed is true, we find nothing at all. The realm of pure Truth, the realm of thinking before the Anstoß is, indeed, as Hegel says a decade later, formless: "The man with sight sees as little in that pure light as in pure darkness, and just as much as the blind man, in the abundant wealth which lies before him." (Hegel 2013: 88) Fichte's aim is to argue that thinking is nothing if not held to account by the shapes of reality, and that can only be accomplished by employing the sharp distinction between what is and what is not. The problem with Kant's notion of a "divine understanding" is that it eliminates the gap between "representation" and what is "given" in experience. Such a "divine understanding" collapses into the form of pure givenness. The world doesn't think, whereas humans do, and it is a distinctive feature of thinking that it picks out both things that exist and things that do not exist. This characterization of thinking as the employment of negatable propositions is how we should read the following metaphor that Fichte offers, in which he characterizes the revelatory power of thinking as 'light' and the concealing, distancing power of negation as 'darkness':

...light and darkness are not posited in opposition to each other as such, but can be distinguished from each other only in degree. Darkness is merely a very small quantity of light. — This is precisely the relationship between the I and the Not-I. (GA I/2: 302; Fichte 2022: 240)

Pure thinking, pure "light" ceases to be thinking at all. Thinking is the combination of positing things that exist and positing things that don't exist. It is the combination of thinking about what is, and thinking about what is not. Fichte pulls apart thinking and being, the I and the Not-I, infinitude and limitation only so that we can see that such a division is a mirage. The "I" and the "Not-I", truth and falsity, affirmation and negation, are not entities in themselves, but rather concepts we employ in making any claim at all.

Thinking without negation is a fantasy. It is the fantasy that the freedom to think any thing at all could be anything other than the freedom to think what is not. It was this fantasy that Kant warned about when he said that "The light dove, cleaving the air in her free flight, and feeling its resistance, might imagine that its flight would be still easier in empty space." (KrV A5/B8; Smith 47) To think without tethering those thoughts to objects given in empirical reality is to build castles in the air, to send thinking into the senseless realm of 'empty space'. While Fichte agrees with Kant on this point, his position (and Hegel's for that matter) is more emphatic. Thinking without resistance is not thinking at all - such thinking cannot even so much as posit a castle in the air. That is because 'resistance' for Fichte refers not to the phenomenon of sensibility, not to our limitation to the "field of appearances" but rather to the self-limitation of thinking. The self-limitation of thinking is the experience of being wrong, and it is this experience of resistance that allows the dove to take flight. Fichte describes it this way:

The activity of the I consists in unrestricted self-positing, in opposition to which there occurs some resistance. If the activity of the I were to give way to this ­resistance, then the activity lying beyond the boundary of this resistance would be utterly annihilated and annulled; and, to this extent, the I would posit nothing whatsoever. (GA I/2: 358; Fichte 2022: 296)

It is not, as Kant took it, that our knowledge is a knowledge of appearances and nothing further. Rather, to think is to push through mere appearance in reaching for the truth. The resistance of thought is that creeping suspicion that maybe I'm mistaken, the realization that I was mistaken, and the cold solace of knowing that maybe now I know how things stand. It can be the despair I feel when my most deeply held assumptions are put to the test, and it can be the relief I feel when I wake up from a fever dream. The resistance that lets thought take flight is reflected in thought's ability to, having considered that things might be one way, determine they are another. Positing, thinking, is the art of "hovering...between opposing directions" (ein Schweben...zwischen widerstreitenden Richtungen), namely between that which is the case and that which isn't (GA I/2: 373, my translation). Thinking, Fichte tells us, is "a resisting activity" (eine widerstehende Tätigkeit) (GA I/2: 370; my translation).

The 20th century representative of this way of understanding negation is Wittgenstein: "this paradox (which indeed has the form of a truism) can...be expressed in this way: one can think what is not the case" (Wittgenstein 2009: §95). Stated in these terms, the conceptual account of the Anstoß seems rather deflationary: we think true thoughts and false thoughts. This seems just to be stating the obvious:

The agreement, the harmony, between thought and reality consists in this: that if I say falsely that something is red, then all the same, it is red that it isn’t. And in this: that if I want to explain the word “red” to someone, in the sentence “That is not red”, I do so by pointing to something that is red. (Wittgenstein 2009: §429)

Fichte's Anstoß is the 'not' that bears on each and every claim, insofar as that claim can be said to be true or false. Even my true, positive claims, such as 'This is red', which appear to have nothing to do with negation, in fact, solely by virtue of being truth claims, have the 'not' always at hand, ready to jump into action, refuting, if need be, that 'This is red' and asserting, instead, that it is not red. Negation is one pole of the compass of truth, always working to orientate me away from my delusional fictions back towards the world as it is. Seen this way, the Anstoß might appear to only limit my thought, to strike down my fantasy and replace it with a slavish sobriety vis-à-vis the facts of life. But that is only half the story. The other half is that I am free to think about things that don't exist. "That is not red," I say, and, in doing so, I bring to mind a world in which that thing could be red. Negation secures a certain distance from just the facts and only the facts, a distance that marks the beginning of what Fichte calls our 'infinitude.'

The Logical Role of Negation

The Anstoß is Fichte's term for negation once, at the conclusion of §4.E., the I's 'infinitude' has come to light. Before Fichte's talk of infinitude in the final section of §4.E., negation, as the forerunner to the Anstoß, is a persistent character in Fichte's argument, helping to construct the 'Not'-I that opposes the I. Fichte derives the Second Foundational Principle of his philosophy, the counter-positing of the Not-I, from the proposition "−A is not = A" (GA I/2: 264; Fichte 2022: 207). Fichte is not clear about what kinds of things 'A' stands for, but in modern logic, we might say that 'A' is a proposition, a truth bearer, that has, as its most basic form 'S is F'. The negation of A, '−A' would then be the contradictory proposition 'S is not F', and the Second Foundational Principle would be derived from the principle of non-contradiction.

Later, in §4.B of the Theoretical Part of the Foundation, Fichte describes the relationship of the I to the Not-I as the partitioning of a certain 'quantity' into 'reality' and 'negation'. Although the Not-I's 'negation' of the I's 'quantity' of 'reality' could be interpreted in physical terms as sensibility impinging on, i.e. 'negating', the 'reality' of my mind, the deeper way to understand these terms is in terms of the truth and falsity of a set of propositions. The I's reality is then the set of all its true propositions about the world, and the I's negation is the set of all its false propositions about the world. The question that Fichte, in Part II of the Foundation wants to answer is how one should understand the nature of negation, how we are to understand the idea that "X negates −X" (GA I/2: 329; Fichte 2022: 268).

Fichte's turn to the infinite comes about when he claims that the I does not have a limited set of possibly true propositions about the world from which to select, but rather that the ability of the I to put forth propositions is unlimited, and since any of these propositions are potentially untrue, the space of epistemic possibility is the infinitely expanding space of any proposition p of the form S is F and its negation −p, or S is not F. The Anstoß is the 'not' that can, but need not, accompany any proposition I put forth.

The presence of negation in a simple claim like 'The sky is blue' is a peculiar kind of presence. In thinking 'The sky is blue' I make no reference to negation. And yet, when challenged, I can explain that by claiming the sky is blue, I am disagreeing with anyone who might want to claim the sky is not blue, or red, or yellow. The presence of negation in judgement is a logical presence with which we, as users of language, necessarily implicitly engage. Fichte doesn't have the philosophical resources to clarify this point, and in lieu of these resources, he resorts to a Kantian language of 'faculties' (Vermögen). The imagination, for example, is a "most wonderful power", i.e. 'faculty', 'Vermögen', by means of which "the positing I brings the vanishing accident to a halt and stabilizes it until it has compared it with the accident that displaces it" (GA I/2: 350; Fichte 2022: 288). In claiming 'The magnet is at rest', in attributing the accident 'at rest' to the magnet, I say nothing about the magnet being in motion. But when asked whether the magnet is in motion, I would answer that I have excluded that possibility based on my claim that the magnet is at rest. Fichte assigns to the faculty of imagination our ability to navigate this infinite space of possible propositions, their contradictory propositions, and their contrary propositions, to hold on to "vanishing accidents" and compare them with other "accidents". At another point Fichte says: "The power of imagination oscillates or hovers [schwebt] in the middle between determination and non-determination, between the finite and the infinite" (GA I/2: 361; Fichte 2022: 298). Fichte's terms are ambiguous here, but any way you slice them, they point to the ability of human beings to navigate between competing claims. Perhaps 'non-determination' refers to our ability to consider two 'determinate' judgements at the same time, like the judgements 'The sky is blue' and 'The sky is not blue'. Perhaps the 'non-determination' Fichte has in mind are negative judgements of the form 'S is not F'. Such negative judgements leave open what 'S' in fact is, and are in that way not 'determinate', and, in fact resemble Kant's description of 'infinite' judgements from the Critique of Pure Reason as judgements that are "infinite in respect of their logical extension" (KrV A73/B98; Smith 108). Either way, the imagination marks humans' capacity to navigate competing claims, i.e. claims that can be true or false, claims which are subject to an Anstoß.¹⁰

Fichte defines a hierarchy of faculties that reflect various stages in our interaction with thoughts, or, propositions. On the lowest rung of the ladder is the 'understanding' (Verstand): "a dormant, inactive power of the mind, the mere receptacle for what is produced by the power of imagination" (GA I/2: 374; Fichte 2022: 310). In the revision of his philosophical system two years later, Fichte would revise his polemic against the understanding, but for now, it stands for the bare simplicity of a thought, that which is only explicit in the simplest form of a claim: 'S is F'. The understanding cannot see beyond exactly what is stated; it cannot, like the imagination, perceive the web of implications that a simple claim entails, such as the exclusion of contradictory and contrary claims. The imagination, in turn, has the shortcoming that it can never settle on a claim; the only faculty that can commit to a claim is reason (Vernunft): "The imagination does not posit any fixed limit; for it doesn't have any fixed standpoint; only reason sets something down, and it does so by first fixating the imagination" (GA I/2: 360, my translation). Fichte concludes the passage just quoted by suggesting that both the imagination and reason continue their work "in the practical field." (GA I/2: 361; Fichte 2022: 298). This suggests that the standpoint of morality is needed to complete Fichte's picture of what it means to have thoughts, what it means to consider, as the imagination does, counterfactuals, and why it is that we, employing reason, commit ourselves to a specific version of the facts and not to another. Fichte makes these intimations of a moral grounding for the imagination and reason in order to motivate his turn to practical philosophy. But exploring the issues of Fichte's practical philosophy is not essential for seeing that, in the Theoretical Part of the Foundation, the Anstoß refers to the constitutive role that negation plays in the free exercise of that distinctly human activity we call 'thinking'.

Conclusions

Why, if the Anstoß simply refers to negation, does Fichte not simply say as much? Why all the word play, the references to an Anstoß, to a 'hovering' imagination that moves in 'opposing directions'? Why the particularly absurd references to "the entire mechanism of the human mind" that Fichte claims he can lay bare (GA I/2: 353, 368; Fichte 2022: 290, 305)? Why would Fichte engage in an interminable double entendre that speaks in the language of physics and mechanism but always signifies the conceptual?

The reason, I believe, is that Fichte is caught flat-footed in his discovery of a philosophical logic. He has at hand standard logical principles, such as the law of identity ("A is A") that he appeals to in his First Foundational Principle of the Foundation and the law of non-contradiction ("−A is not = A") that he appeals to in his Second Foundational Principle (GA I/2: 256, 264; Fichte 2022: 201, 207). However, when it comes to transforming these logical principles into a metaphysical logic, into a logic that perambulates not just the abstractions of thinking, but rather "the dependence of thinking on being", he is at a loss for words (Kimhi 2018: 123). The best he can do is use language in new ways, leaning heavily on obscure terms like 'positing', 'infinitely outgoing activity', and the 'check'. Fichte's goal is clearly not to further obscure the obfuscations of Kant's appeal to inscrutable transcendental principles like 'sensibility'. But in lieu of the language of metaphysics that Hegel would only develop a decade later, he makes do with what he has.

In Part III of the Foundation, the Foundation of the Science of the Practical, Fichte engages in a remarkable moment of self-reflection about the deficiencies of his formulations. Picking up a theme that began to occupy him during the drafting of the first two parts of the Foundation, namely language's inability to capture the depth of his philosophical insight, Fichte writes: "The Wissenschaftslehre is the kind of philosophy that can be communicated only through the spirit and by no means through the mere letters" (GA I/2: 415; Fichte 2022: 345).¹¹ Fichte offers the reader a novel strategy for trying to grasp this so-called 'spirit' of his philosophy. One must, namely, 'hover between' the competing claims of idealism and realism, and this, he says, can only be accomplished "by the power of imagination" (GA I/2: 415; Fichte 2022: 345). We can formulate Fichte's thought here this way. Let us assume, for the sake of argument, that only that is real which is given in experience. Thoughts, in contrast, are not real at all, but rather ideal. The mystery that Fichte is getting at is the irreality of thought. How is it that these ideal things have anything to say at all about what is real? For it is not simply a matter of correctly employing or not employing the negation sign, though that is certainly part of it. Rather, the true mystery is why, thinking anything, I think anything at all.

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