THE LIMITS OF SENSE AND REASON: A Line-By-Line Critical Commentary on Kant’s “Critique of Pure Reason,” #10–Discursive vs. Intuitive Clarity, & The Alleged Unclarity of the CPR.

By Robert Hanna

[I] was then making plans for a work that might perhaps have the title, “The Limits of Sense and Reason.” I planned to have it consist of two parts, a theoretical and a practical. The first part would have two sections, (1) general phenomenology and (2) metaphysics, but this only with regard to its method. (Letter to Marcus Herz, 21 February 1772 [C 10: 129])



Previous Installments:

#1: Introduction to The Limits of Sense and Reason

#2: Bii/GW91 The Motto

#3: Aiii/Biii/GW93–97 The Dedication

#4: Avii-ix/GW99 Preface to the First (A) Edition.

#5: Axi note/GW100–101 Preface to the First (A) Edition

#6: Axi note/GW100–101 Preface to the First (A) Edition

#7: Axii-xiv/GW101–102 Preface to the First (A) Edition

#8: Axv-xvi/GW102–103 Preface to the First (A) Edition

#9: Axvi-xvii/GW103 Preface to the First (A) Edition

A Note on References to Kant’s Works


The first five installments in this series followed the 2019–2020 version of THE LIMITS OF SENSE AND REASON, aka LSR.

Starting with installment #6, subsequent installments follow the revised and updated 2021 version of LSR.

In any case, you can read or download a .pdf of the complete text of the 2021 version of LSR HERE.

Because LSR is an ongoing and indeed infinite task, revised and updated .pdfs of the complete text will be uploaded to that URL on a regular basis.


CPR TEXT Axvii-xx/GW103–104 Preface to the First (A) Edition

Finally, as regards clarity,a the reader has a right to demand first discursive (logical) clarity, through concepts, but then also intuitive (aesthetic) clarity, Axviii through intuitions, that is, through examples other illustrations in concreto. I have taken sufficient care for the former. That was essential to my undertaking but was also the contingent cause of the fact that I could not satisfy the second demand, which is less strict but still fair. In the progress of my labor I have been almost constantly undecided how to deal with this matter. Examples and illustrations ways appeared necessary to me, and hence actually appeared in their proper place in my first draft. But then I looked at the size of my task and the many objects with which I would have to do, and I became aware that this alone, treated in a dry, merely scholastic manner, would

a Deutlichkeit

suffice to fill an extensive work; thus I found it inadvisable to swell it further with examples and illustrations, which are necessary only for a popular aim, especially since this work could never be made suitable for popular use, and real experts in this science do not have so much need for things to be made easy for them; although this would always be agreeable, here it could also have brought with it something Axix counterproductive. The Abbé Terrasson says that if the size of a book is measured not by the number of pages but by the time needed to understand it, then it can be said of many a book that it would be much shorter if it were not so short. But on the other hand, if we direct our view toward the intelligibility of a whole of speculative cognition that is wide-ranging and yet is connected in principle,a we could with equal right say that many a book would have been much clearer if it had not been made quite so clear. For the aids to clarity helpb in the parts but often confuse in the whole, since the reader cannot quickly enough attain a survey of the whole; and all their bright colors paint over and make unrecognizable the articulation or structure of the system, which yet matters most when it comes to judging its unity and soundness.

It can, as it seems to me, be no small inducement for the reader to unite his effort with that of the author, when he has the prospect of carrying out, according to the outline given above, a great and important piece of work, and that in a complete and lasting way.

Axx Now metaphysics, according to the concepts we will give of it here, is the only one of all the sciences that may promise that little but unified effort, and that indeed in a short time, will complete it in such a way that nothing remains to posterity except to adapt it in a didactic manner to its intentions, yet without being able to add to its content in the least. For it is nothing but the inventory of all we possess through pure reason, ordered systematically. Nothing here can escape us, because what reason brings forth entirely out of itself cannot be hidden, but is brought to light by reason itself as soon as reason’s common principlec has been discovered. The perfect unity of this kind of cognition, and the fact that it arises solely out of pure concepts without any influence that would extend or increase it from experience or even particular intuition, which would lead to a determinate experience, make this unconditioned completeness not only feasible but also necessary. Tecum habita, et naris quam sit tibi curta supellex. — Persius.d

a Princip

b Kant’s text reads “fehlen” (are missing). We follow Erdmann, reading helfen.

c Princip

d “Dwell in your own house, and you will know how simple your possessions are” (Persius, Satires 4: 52).



In a shift of topic that’s unintentionally quite ironic, given his own immediately preceding discussion of the Deduction, Kant then turns to a discussion of the topic of clarity or Deutlichkeit, the second epistemic condition of adequacy on the critique of pure reason.

Descartes, Leibniz, and the other classical Rationalists had freely used the notion of cognitive clarity (i.e., epistemic salience) alongside the notion of cognitive notion of distinctness (i.e., epistemic individuation).

According to Kant, however, there are two importantly different types of clarity:

(i) discursive or logical clarity, via concepts, and

(ii) intuitive or aesthetic clarity, via intuitions.

Since Kant hasn’t yet explicitly defined either the notion of a “concept” (Begriff) or the notion of an “intuition” (Anschauung) — nor, in fact, somewhat maddeningly, does he actually explicitly define them until A320/B376–77 — this is bound to be quite confusing to the reader of the A Preface.

The one partial characterization that he does give here is that intuitions provide “examples or other illustrations in concreto.”

As I’ve mentioned already, concepts for Kant are essentially general mental representations of objects and cognitive devices of description.

Concepts stand for or pick out properties or universals in the world, and apply to or subsume all the actual or possible objects that fall under or instantiate those properties or universals.

Concepts, when they’re objectively valid, also function as normative rules for judgmentally cognizing logically-structured objects of experience, namely, sense-perceptual facts or states of affairs that are actual or possible objects of the natural sciences.

For my purposes in commenting on the A Preface, the only other characterization that’s directly relevant is that all concepts have

both (i) an intension — that is, an ordered package of descriptive information — or Inhalt,

and also (ii) a comprehension or Umfang — that is, an extension consisting of all the actual or possible objects descriptively specified by the intension.

Hence the discursive or logical clarity of a concept consists in the epistemically salient presentation of either its intension or its comprehension.

By contrast, either pure or empirical intuitions of our sensibility are essentially non-conceptual mental representations of individual manifestly real objects and cognitive devices of direct singular reference.

Intuitions stand for or pick out individual apparent objects in the manifestly real world, and are essentially relational in the sense that if a cognition doesn’t actually stand for or pick out an individual object, then that cognition isn’t an intuition.

So necessarily, if cognitive subject X sensibly intuits individual object Y, then X actually exists and Y actually exists.

Hence the intuitive or aesthetic clarity of an intuition consists in the epistemically salient presentation, via our sensibility, of an actually existing object.

The term “aesthetic” here, as used by Kant, means perceptual or sensible, and not (specifically) beautiful or artistic.

And I’ll have more to say about the term “aesthetic” when I comment on the Transcendental Aesthetic chapter.

In the rest of the paragraph, Kant then applies this distinction between the discursive or logical clarity of concepts and the intuitive or aesthetic clarity of intuitions to the presentational format, organization, and style of CPR.

He’s made a special effort, he says, to satisfy the normative standard of discursive or logical clarity.

But the same isn’t true, he says, of the normative standard of intuitive or aesthetic clarity: i.e., he hasn’t made a special effort to make the CPR intuitively or aesthetically clear.

Kant then offers an apology (in the classical justificatory sense of an apologia) for CPR’s lack of examples, its “dry, merely scholastic manner,” and its great length (856 pages in the A edition, and 884 pages in the B edition).

This apologia has some autobiographical significance, and it also makes a larger philosophical point.

The autobiographical significance is that Kant’s first well-known publication was his 1764 Observations on the Beautiful and the Sublime, which gave him the reputation of being an excellent writer and an important literary intellectual, and in fact brought about the offer of a professorship of poetry at University of Königsburg.

He declined this offer because he wanted the forthcoming Königsburg professorship in logic and metaphysics, and thereby took a calculated risk that his scholarly reputation was then sufficiently on the rise, that he’d ultimately be able to secure that professorial Chair.

This wasn’t a small thing for an academically ambitious 40 year-old Privatdozent in search of an established professorship, which were far rarer and even more difficult to obtain than they are today, when of course they’re still very rare and difficult to obtain.

Fortunately for him, however, Kant did indeed get his Königsburg logic and metaphysics professorship in 1770, having previously turned down other offers of professorhips at Erlangen and Jena in 1769 and 1770.

So the academic career gamble paid off.

But obviously, even seventeen years later, he also still thought enough about the time when his literary reputation was in the acsendancy, to be a little embarrassed by the relentlessly stodgy, unstylish organization of the CPR.

The larger philosophical point is a metaphilosophical one about metaphysical treatises.

Kant says here that the great length of CPR necessitated deleting many “examples and illustrations” that were included in the first draft.

Still, he thinks that such examples and illustrations are really necessary only in books intended for a “popular” (that is, relatively well-educated, and middle class or higher) audience.

And, he says, philosophical experts will not need the extra intellectual labor-saving devices, which, as nice as they might be, may in fact impede their understanding of CPR.

But why would this impediment to understanding CPR occur?

By way of an answer, Kant then cites the French philosopher Jean Terasson’s witticism to the effect that if the true size of a book is to be gauged by the time needed to understand it, then many books would have been much shorter if they had not been so short.

Kant’s equally witty spin on this, with regard to “the intelligibility of a whole of speculative cognition that is wide-ranging yet is connected in principle” — that is, with regard to the intelligibility of a metaphysical system — is that many books would have been much clearer if they had not been presented so clearly.

In other words, he’s saying that it’s possible, even for philosophical experts, to fail to grasp the overall “articulation and structure” of a metaphysical system, through being distracted by examples and illustrations which are intended only to illuminate its proper parts.

Indeed, attaining “a survey of the whole” (Überschauung des Ganzen) is essential when properly evaluating the coherence and truth of the metaphysical system.

Kant uses an illuminating architectural analogy here.

Grasping a metaphysical system is like looking at the complete working drawings of a house.

This, in turn, confers a special cognitive-semantic status on metaphysical treatises.

For they are the only scientific works that hold out the prospect of actually completing the intellectual projects on which they are based, at least in as far as their essential content is concerned.

This is because metaphysical treatises, if correct, specify complete systems of pure human reason.

Here Kant again deploys, at least implicitly, The Reflexive Transparency Assumption and The Pure General Logic Assumption:

Nothing here can escape us, because what reason brings forth entirely out of itself cannot be hidden, but is brought to light by reason itself [that is, The Reflexive Transparency Assumption is true] as soon as reason’s common principle (gemeinschaftliche Prinzip) has been discovered. The perfect unity of this kind of cognition, and the fact that it arises solely out of pure concepts without any influence that would extend or increase it from experience or even particular intuition, which would lead to a determinate experience, make this unconditioned completeness not only feasible but necessary. [that is, The Pure General Logic Assumption is true.] (CPR Axx, non-square-bracketted boldfacing in the original)

The quotation from Persius — Tecum habita, et noris quam sit tibi curta supellex, namely, “Dwell in your own house, and you will know how simple your possessions are” (CPR Axx) — then neatly closes out the architectural metaphor.

The reflexively transparent relation of human reason to itself, via pure general logic, is just like an architect who lives in the very house he has designed and built with his own hands.

In this connection, it seems satisfyingly ironic and also historically apt that the young Ludwig Wittgenstein, in the Preface to his 1921 Tractatus, 140 years after the publication of the CPR, like Kant, also claimed to have finally brought metaphysics and pure logic to their completion, and again like Kant, also claimed that this was a reflexively transparent and even trivial enterprise:

[T]he truth of the thoughts communicated here seems to me unassailable and definitive. I am, therefore, of the opinion that the problems have in essentials been finally solved. And if I am not mistaken in this, then the value of this work secondly consists in the fact that it shows how little has been done when these problems have been solved.[i]

Then Wittgenstein gave up philosophy, and as his next major project in the mid-1920s, helped to design, along with the architect Paul Engelmann, and build, with his own hands, a real house, the Haus Wittgenstein, for his sister Margaret Stonborough-Wittgenstein (who, incidentally, had her now-famous wedding portrait painted by Gustav Klimt in 1905).

And then it seems equally satisfyingly ironic and also historically apt that Wittgenstein’s eldest sister Hermine later said this about the Haus Wittgenstein:

Even though I admired the house very much, I always knew that I neither wanted to, nor could, live in it myself. It seemed indeed to be much more a dwelling for the gods than for a small mortal like me.[ii]

The same, really, is true of the Tractatus.

The Tractatus presents a logico-linguistic transcendental idealism designed for a single metaphysical subject that’s in effect one of the “terrifying angels” of Rilke’s Duino Elegies,[iii] not for “human, all too human” cognizers like us.

Correspondingly — to loop this brief Tractarian excursus back to CPR — the underlined phrases in what Hermine said, ironically underline the very same anthropocentric turn point that Kant makes in the B edition CPR’s Baconian Motto.


[i] L. Wittgenstein, Tractatus Logico-Philosophicus, trans. C.K. Ogden (London: Routledge & Kegan Paul, 1981), p. 29.

[ii] S. Jeffries, “A Dwelling for the Gods,” The Guardian (5 January 2002), underlining added.

[iii] See R. Hanna, “Wittgenstein and Kantianism,” in H.-J. Glock (ed.), Blackwell Companion to Wittgenstein (Oxford: Blackwell, 2017), pp. 682–698; and R.M. Rilke, “Duino Elegies,” in R.M. Rilke, The Selected Poetry of Rainer Maria Rilke, trans. S. Mitchell (New York: Vintage, 1989), pp. 150–223, first elegy, line 6 (p. 151), and second elegy, line 1 (p. 157): “Every angel is terrifying” (Jeder Engel ist schrecklich).


Mr Nemo, W, X, Y, & Z, Monday 15 March 2021

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Mr Nemo

Mr Nemo

Formerly Captain Nemo. A not-so-very-angry, but still unemployed, full-time philosopher-nobody.