By Wayne Waxman
Kant’s Anatomy of the Intelligent Mind (henceforth KAIM) is the focus of the outstanding, much appreciated discussion pieces authored by John Callanan and Colin McLear. KAIM is the second of two volumes—the first being Kant and the Empiricists: Understanding Understanding (Waxman 2005) (KEUU)—of a single work on self and understanding in Kant and British empiricism. It comprises a four-chapter general introduction relating Kant to the empiricists as successive stages in the development of psychologism; a five-chapter Locke part; a five-chapter Berkeley part; a six-chapter Hume part; and a full volume devoted to Kant’s psychologism. Although written as a single, integral whole, each segment is cast so as to be readable on its own. Only when readers take issue with something I say about a philosopher in a part of the work subsequent to my treatment of that philosopher’s views are they urged to acquaint themselves with the scholarly case I make, say, in the Berkeley part, that supports something I say about Berkeley in the Hume or Kant part.
Recognising that a two-volume, 1200-page treatise will be difficult for even the most dedicated to digest, I have recently published a new, much briefer book that takes for granted the scholarly case presented in my four previous books in order to focus exclusively on the idea that everywhere informs it. It is called A Guide to Kant’s Psychologism via Locke Berkeley Hume and Wittgenstein (Routledge 2019). A book with this brief is needed because compliance with scholarly desiderata can obscure or even run at cross purposes to philosophical understanding, especially in the case of an idea as unfamiliar as a priori psychologism is, not only to philosophers generally but to Kant scholars in particular. So, in order to equip themselves with the philosophical understanding needed to properly evaluate my scholarly work, I strongly urge Kant scholars unfamiliar with it to study the new book first.
Replies to John Callanan
I. Psychologism is a Species of Psychological Philosophy, not a Synonym
1. I marvel at the fact that no matter how many times I spell it out in KEUU and KAIM, or how many different ways I contrive to say it, so few Kant scholars seem to get that psychologism, as I understand and employ the notion, is a unique species of, not a synonym for, psychology (psychological philosophy, philosophical psychology). I repeatedly get the refrain “Waxman, your take on Kant is not nearly as original as you make it out to be; Kitcher, Brook, and many others also approach Kant’s philosophy from a psychological perspective”. Kant’s keen interest in psychological matters is obvious to any reader, and scholarly focus on it long predates me, Kitcher, et al (e.g. Pierre Lachièze-Rey and Hermann Mörchen). But psychology is not psychologism. Psychology, in the sense relevant to Kant, is exemplified by the early modern ‘theory of ideas’ that concerned itself with the origin of notions familiar from language as conscious representations in the mind. But if the notion at issue is non-psychological, and particularly if it is deemed a priori and/or objective—as commonly is the case with logical, mathematical, scientific, and metaphysical notions—then, while a psychological account of its origin in us may be interesting and even have important epistemological implications, it can tell us nothing whatsoever about the notion itself—its meaning, the scope of its application, or its origin—and, for these reasons, does not yet count as psychologism.
2. Kitcher et al may emphasise the psychological components of Kant’s philosophy but, so far as I can detect, they treat it as anti-psychologistic to its core. Their Kant consequently slots neatly into the anti-psychologistic consensus that leaves his philosophy fundamentally indistinguishable from the kind of platonistic Rationalism one finds in Leibniz or Wolff and more recent platonist variants such as P.F. Strawson’s connectionist interpretation and its many offshoots. The a priori psychologism I attribute to Kant in KEUU/KAIM, by contrast, is fundamentally incompatible with platonism of every kind.
3. Psychologism should not be understood as a matter of invoking psychological capacities as truth conditions of sentences or anything else epistemological in nature. It is instead a psychological method of explicating the meaning of ostensibly non-psychological concepts by investigating whether there are any essential elements of their content that can have no source other than consciousness; if so, then they cannot be applied in consciousness-independent contexts without contradicting the very condition of their meaningfulness. Hume, for example, utilised psychologistic explication to show that all our notions of the cement of the universe—space, time, causality, identity at and through time, substantiality, etc., i.e. everything generally supposed to be objective save logic and mathematics—depend on associative consciousness for essential elements of their content, and so can no more be conceived to retain their meaning in consciousness-independent contexts than a fermion can meaningfully be supposed to be stoically undergoing agonies of pain. Kant’s a priori psychologism is an even more extreme case: by going so far as to bring logic and mathematics within its scope in addition to space, time, causality, substance, etc., it leaves us totally bereft of the means to consciously represent consciousness-independent reality, which consequently vanishes into the oblivion he designated by such terms as ‘thing in itself’ ‘transcendental object=X’ and ‘noumenon in the negative sense’. In other words, Kant’s psychologism purports to render physical and metaphysical accounts of consciousness-independent reality complete non-starters by demonstrating that we lack the representational wherewithal even to ask the questions such accounts are meant to address. This, in my view, is the nub of Kant’s critique of dogmatic metaphysics.
4. No instance of psychologistic explication is more fundamental or consequential for Kant’s philosophy than the explication of logical universality by the ‘I think’ under the denomination analytic unity of apperception at B133–4n, discussed in KAIM, Chapter 9. This is psychologism in its purest, most notorious form: explicating the logical psychologically. Who else among recent commentators has said this is true of Kant or made it central to his or her interpretation? In particular, without the psychologistic explication of logical universality in terms of the ‘I think’, the most original and important component of the interpretation presented in KAIM—the category-by-category elucidation of transcendental synthesis in KAIM, Chapter 15—could not have even gotten to square one, much less proceeded to show how Kant’s claim to be able to explain how sensibility can unite with understanding to yield cognition without committing transcendental amphiboly can be sustained.
5. Neglect of the fundamental differences between psychologism and psychology also seems to me a major factor in the failure to appreciate how interpreting Kant’s philosophy as psychologism allows it live up to its billing as a genuine Copernican-scale revolution better than any alternative. Instead of explicating consciousness in terms of logic, science, mathematics, or metaphysics, my psychologistic Kant explicates logic, science, mathematics, and metaphysics in terms of consciousness. What could be more revolutionary than that? And what could be less revolutionary than supposing Kant rejected Hume’s empirical psychologism merely in order to revert to a conception of representational understanding barely distinguishable from pre-Humean platonistic Rationalism?
II. How (Not) to Understand the Transcendental Aesthetic
The Transcendental Aesthetic of the Critique of Pure Reason and the corresponding part of the Prolegomena are tasked to demonstrate that space and time are pure (not empirical) intuitions (not concepts) of sensibility (not understanding). To prove this, a number of arguments are offered, most invoking objective-cognitive factors (limitation, partition, composition, construction, etc.), including considerations drawn directly from geometry and natural science. From these arguments, the conclusion is reached that space and time are inextricably bound up with something ineluctably subjective (making them ideal), a subjective component that yet is not empirical (precluding their being empirically ideal), but instead both a priori and essential for cognition (making space and time not merely a priori but transcendentally ideal).
Callanan appears to believe that the focus for scholarly analysis should be the arguments, taken in isolation both from one another and from subsequent portions of the Critique and the Prolegomena, so that once they are put into proper, enumerated argument form, it can be determined if Kant’s reasoning is valid and sound, and his positions assessed accordingly. I say this because he complains at some length that KAIM fails in all these regards, making it unnecessarily, and culpably, vague as to just what Kant is supposed to be arguing for or how, most particularly in the cases of geometry and transcendental idealism.
It is fine for Callanan to approach the Aesthetic as he chooses, but I do not think it fair to fault KAIM for rejecting that approach and pursuing a different one. The view articulated in KAIM is that Kant’s ‘official’ arguments—at least the ones simple and straightforward enough to be usefully recast in argument form with enumerated premises—are the least interesting parts of the Critique, and, if taken in isolation the way Callanan seems to advocate doing, tend to obscure more than they reveal. Such arguments are instead merely the tip of the iceberg of Kant’s real reasoning, of which by far the most important part is conceptual: identifying which concepts matter, sharply delineating them, distinguishing them from any they might be conflated with, relating and ordering them, applying them to various philosophical problems, and refining their analyses in the light of those applications to make them as definitive as possible.
Not coincidentally, the Aesthetic is divided into expositions of concepts (of space and time), conclusions drawn from these conceptual expositions (e.g. transcendental idealism), followed by an elucidation in which Kant defends his expositions of/conclusions from those concepts against objections, and concludes with some general observations inspired by the concepts’ expositions. The analysans of these expositions is pure sensible intuition. But intuition, as every reader of Kant knows, is only half of the cognitive equation: a concept is required before intuition can be raised to Erkenntnis. Concepts are of course the doing of discursive understanding, not sensibility. Since Kant could not have been clearer that we cannot hope to comprehend what a pure intuition of sensibility is unless and until we abstract from everything owing to discursive understanding (A22/B36), I see it as the first obligation of the interpreter to strive to bracket out anything in any way involving discursive understanding that enters into the cognitive considerations invoked in the arguments presented in the Aesthetic.
Take for example geometry and physics. Since geometry is impossible apart from the concepts that enter into its definitions, axioms, postulates, and theorems, and since for Kant the possibility of geometry and mathematics generally is predicated on transcendental discursivity (the ‘I think’, the pure concepts of the understanding, and transcendental syntheses in accordance with these concepts), nothing properly mathematical can be supposed to enter into the content of space and time qua nondiscursive pure intuitions of sensibility. Similarly, since physics is impossible apart from the empirical concepts of corporeal nature that everywhere inform its principles and propositions, and since for Kant the possibility of physics and objective empirical cognition generally is predicated on transcendental discursivity, nothing proper to natural science can be supposed to enter into the content of space and time qua nondiscursive pure intuitions of sensibility. This is why the arguments offered in the Aesthetic that invoke factors inextricably bound up with discursive cognition can obscure more than they reveal: one can easily be misled into supposing, for example, that these intuitions can be both nondiscursive and intrinsically Euclidean and/or Newtonian. It thus becomes vital to deprioritise the arguments in favour of the Aesthetic’s real business of expounding the concepts of space and time as pure intuitions of sensibility.
Another way to put the point is that before one can hope to understand the Aesthetic, one first has to look beyond it, to the Transcendental Analytic, in order to discover all that the understanding contributes to representations of space and time, bracket it out completely, and then return to the Aesthetic to determine which of its contents are and are not truly relevant to the status of space and time as pure intuitions of sensibility. That is what I do in KAIM, Chapters 3–4. My procedure was to draw on Kant’s entire corpus to extract the conceptual core of his various arguments in the Aesthetic, integrate those conceptions, and thereby synthesise a single, unified conception of what exactly a pure intuition of sensibility is. It is, after all, one of the few notions Kant claimed to be the first to have discovered, and, insofar as transcendental idealism falls directly out of it, it is also the notion he used to distinguish his philosophy from all others.
III. Kant’s Psychologistic Explications of Space, Time and Nature Accommodate Riemannian Geometry and Post-Newtonian Physics
1. I agree with Callanan that Kant held “that empiricism must be rejected simply because it renders mathematical truths contingent”. But there are three senses in which synthetic a priori mathematical judgements count as contingent from Kant’s transcendental perspective that Callanan overlooks. First, in contrast to analytic judgements, the negation of a synthetic a priori mathematical judgement is thinkable. For example, it is perfectly possible to think that space has more than three dimensions, whereas it is impossible even to think that gold is non-metallic (see discussion in KEUU, Chapter 2). Second, considerable textual evidence is adduced in KEUU and KAIM to show that Kant held that not only geometry but mathematics generally is contingent on minds constituted like ours. Different forms of sensibility would make geometry, arithmetic, et al, quite impossible, and set something else in their place—something unimaginable to be sure but still quite thinkable. But even with the same forms of sensibility as ours, a creature with different forms of judgement/pure concepts of the understanding—which Kant refused to preclude, e.g. at B145–6 and A230/B283—also could not have geometry (because e.g. the pure concept of limit would be lacking), arithmetic (because e.g. the concept of number would be lacking), or anything else we comprehend under the term ‘mathematics’, but would instead have something quite different in their place. Third, and the sense of contingency most directly relevant to my interpretation of Kant’s account of mathematics and science in KAIM, is the simple fact that transcendental notions (here I include not only the pure concepts of the understanding but the pure intuitions of sensibility and the ‘I think’) are completely devoid of properly mathematical and empirical-scientific content, making it contingent on mathematics to determine, by the methods unique to it (ostensive and symbolic construction), which synthetic a priori mathematical judgements are and are not true, and contingent on science to determine by observation and experiment which scientific concepts and principles in any given era are truest of nature.
2. KAIM, Part II shows that space and time, prior to and independently of transcendental synthesis of their manifolds conformably to pure concepts of the understanding, are so completely undifferentiated and indeterminate as to be entirely devoid of mathematical determinateness, be it mereological, arithmetic, or any other. KAIM, Parts IV and V further show that such differentiation and determination as transcendental synthesis is able to confer on space and time suffice only to make pure and applied mathematics possible, but without yielding the slightest properly mathematical determinateness. For example, the space that emerges from transcendental synthesis is neither Euclidean nor Riemannian, but is determinable either way and, most importantly so far as Kant was concerned, determinable completely a priori. ‘A priori’ signifies that a mathematical synthetic judgement is both necessary and universal, meaning that its truth in no way depends on experience and nothing experience can disclose can ever contradict it. But this, as I read Kant, is to say no more than that whatever geometers succeed in constructing, be it in Ancient Greece, Enlightenment Europe, or on some 34th century terraformed planet in another solar system, will count as synthetic a priori, and so be necessarily and universally true in a sense completely immune to empirical contingency. Thus, “whatever geometers construct” necessarily (not contingently!) includes what Riemann constructed in the 19th century, what geometers and topologists today construct, and whatever future mathematicians may succeed in constructing.
3. A case in point is the three dimensions example at B41. Callanan overlooks the fact that Kant cites the proposition that space has three dimensions as an example of geometrical, not transcendental synthetic a priori truth. It is thus perfectly consistent with my reading of Kant’s transcendental philosophy as leaving it to geometry to settle the question of how many dimensions space has. Since the only geometry in Kant’s time was Euclidean, only three-dimensional space met the era’s standards of geometrical construction. But, as I argue in KAIM, Chapter 15, the objective space yielded by transcendental synthesis is perfectly able to accommodate a space with higher dimensionality, including infinitely many. So, on my reading, the fact that 19th century geometers discovered how to construct higher dimensional spaces poses no problem for Kant’s transcendental philosophy.
4. My case against Kant’s putative Newtonian dogmatism is similar to my rebuttal of the Euclidean dogmatism charge: just as the products of transcendental synthesis have no properly mathematical implications but only serve to make mathematics in general possible, they have no properly scientific implications but merely serve to make science (and empirical cognition generally) possible (KAIM, Part V). In both cases, when interpreters suppose Kant to be dogmatic it is because they are misled by his use of his era’s highest exemplars of mathematics and science into conflating his claim to explain the possibility of mathematics and science from a priori grounds alone with a dogmatic assertion that geometry can never be other than Euclidean or physics anything other than Newtonian.
5. I doubt if Callanan will be convinced by these considerations. So, I challenge him or anyone else who disputes my reading to present an analysis like the one I offer in Chapter 15, showing that when transcendental synthesis is fully worked out, there emerges a space and time that are not just able to accommodate mathematics and physics (i.e. make them possible), as I contend, but a space and time which imply the truth of Euclidean geometry/falsehood of non-Euclidean geometry or the truth of Newtonian physics/falsehood of relativity theory and quantum theory—if not analytically then synthetically, if not synthetically then imply it in some other way. If you cannot do that, then you have to concede that Kant’s transcendental philosophy does not have these consequences. And afterward, with your previous certainty shaken, I invite you to reread what Kant actually says and I suspect you will end up agreeing with me that there is in fact nothing remotely close to a commitment to dogmatic Euclideanism or dogmatic Newtonianism to be found there.
IV. General logic
Callanan complains that “it would have been interesting to hear some gesture as to how [the psychologistic explication of logical universality by the analytic unity of apperception in KAIM, Chapter 9] might be thought to relate to the representational status of logical operators”. One only has to look in the right places to find a great deal more than a “gesture”. KAIM argues that by Kant’s criteria of the logical, mathematical logic counts as mathematics rather than logic. So, KAIM’s answer to Callanan is that mathematical logical operators, from truth-functional logic to quantification theory set theory and beyond, should all be understood on the same principles Kant utilised to explicate mathematical operators and functions generally. Relevant discussions can be found in KEUU, Chapter 4-B and KAIM, Chapters 6-E, 10, and 14-E.
Callanan also complains that “it would have been helpful to hear how [the KAIM, Chapter 9] account relates to the principles of identity and of non-contradiction”. KAIM explains Kant’s principles of identity and contradiction as relating to the matter (i.e. content) of concepts, not their logical form as universals. Since the (numerical apperceptual) identity mentioned in the passage cited by Callanan concerns not the matter but merely the form of concepts as logically universal, there was consequently no call to explain how it relates to the principles of identity and contradiction.
Earlier I emphasised the preeminence of conceptual distinctions in Kant. Had Callanan attended more carefully to Kant’s distinctions between logic and mathematics and between principles of logical form (apperception) and principles of logical matter (identity and contradiction), he might have been able to engage more productively with KAIM’s analysis of general logic.
V. Secondary literature
It is said early in KAIM that anyone interested in my take on secondary literature should consult the extensive treatment of it in my earlier book, Kant’s Model of the Mind (Waxman 1991). Since hardly anyone in the interim had even mentioned, let alone addressed the criticisms or discussed the alternatives developed in Kant’s Model, I did not see much point in further lengthening and complicating KAIM by repeating myself there.
Replies to Colin McLear
VI. KAIM Never Asserts or Implies that Unity of Sensibility/Prediscursive Apperception is Necessary to the Conception of Sensibility
1. McLear’s discussion of KAIM on sensibility is seriously skewed by misinterpreting it as maintaining that unity of sensibility (= prediscursive apperception) is necessary to the conception of sensibility itself. KAIM’s treatment of sensibility focuses throughout on Kant’s account of the sensibility of multi-sensory apperception-capable minds like the human mind—this for the simple reason that that is what the Critique of Pure Reason and virtually all of Kant’s other writings focus on. Animal sensibility is ignored in the Transcendental Aesthetic and plays no part in Kant’s discussion of the relation of sensibility to pure understanding in the Transcendental Analytic. These parts of the Critique focus entirely on human and human-type minds from the vantage of its supreme principle of apperception. To repeat: nowhere does KAIM state or imply that being a necessary condition of the sensibility of a multi-sensory apperception-capable mind like ours is, for Kant or anyone else, the same as being a necessary condition of all sensibility as such; quite the contrary in fact.
2. To say that apperception is a necessary condition for sensibility is to say that sensibility is impossible unless capacities for sensation are complemented by imagination and the capacity for the representation ‘I think’. McLear can present no evidence to indict KAIM of subscribing to that absurdity because none exists. On the contrary, it is quite clear in both KEUU and KAIM that the minimal sufficient condition for sensibility is sensation, which even Locke’s oyster, with its one dull perception distinguishing it from perfect insensibility, can boast of.
3. McLear apparently overlooked the entry in the index that points to p. 349, where I say that, like Hume before him, Kant deemed association well within the capacity of animal minds, and I reference five passages in support of this, including citations from two. The texts I reference make clear that Kant held that animals show unmistakable signs of having sensations, i.e. sensibility; consciousness of sensations in perception; and some ability to compare their perceptions short of being able to cognise objects through them (i.e. animals kennen but do not erkennen).
4. Yet, while not denying that animals have non-apperceptual conscious representation, Kant was careful not to assume that theirs is anything like ours:
Beasts lacking understanding do indeed have something similar to what we term representations (because it agrees in its effects with what in human beings are representations), though [it] may perhaps be entirely different—but no cognition of things. (Anth, AA 7:397, my underlining; one of the texts referenced on KAIM, p. 349)
So, while McLear is right to say that my version of Kant cannot ascribe a synthesis of apprehension in intuition for representing the sensible manifold as a manifold to animals if the intuition in question involves pure intuitions and pure intuitions are instances of prediscursive apperception, my reading does not preclude the ability of animals to represent their manifold entirely differently.
5. Let McLear come up with a single text in which Kant ascribes apprehension in intuition under pure intuitions of sensibility to animals and I might have a problem. Failing that, we have to live with the fact that Kant was silent on the workings of animal sensibility, saying only that its effects resemble the effects of those features/capacities of human sensibility that are prior to and independent of the capacity for apperception.
VII. ‘Discursive’ Signifies Representation by Means of Concepts
McLear gets Kant wrong and so muddies his discussion of KAIM when he denies that Kant understood ‘discursive’ to signify “representation by means of concepts” and instead cites A99 to claim that it means “running through and gathering together”. A99 is part of Kant’s discussion of the imagination’s synthesis of apprehension in intuition, which, as concerned with intuition rather than concepts, I take to exemplify nondiscursive representation (representation without concepts). It is worth noting that the word ‘discursive’ does not occur at A99 or indeed anywhere else in the Transcendental Deduction of the Categories. McLear evidently conflates Kant’s notion of synthesis, which need not involve concepts (e.g. apprehension and reproduction), with his notion of discursivity, which invariably does.
KAIM cites A24–5/B39, A31/B47, A68/B93, Log, AA 9:58, and FM, AA 20:325 as instances where ‘discursive’ is used in the sense of ‘representation by means of concepts’ (= judgement), but that is only a partial list. Nor, as far as I am aware, is ‘discursive’ used anywhere in Kant’s corpus in connection with non-conceptual representation.
Bottom line: for Kant, representation is nondiscursive if no concepts are involved; and any representation that precedes and makes possible discursive representation is ipso facto prediscursive.
VIII. Denying that Apperception is Ever Prediscursive and Precategorial is Viciously Circular
The gist of the argument in KAIM that the denial of prediscursive, precategorial apperception is viciously circular is as follows. If one supposes that the categories are necessary conditions of unity of apperception (as almost every Kant scholar does), one has to reckon with the fact that Kant expressly asserted that the analytic unity of apperception (henceforth AUA) is essential to all conceptual representation as such (B133–4n). Since the categories are pure concepts of the understanding, the implication is clear: they presuppose AUA as their ground and so cannot be supposed to precede and make possible AUA without vicious circularity (see also A341/B399–400, A348/B406, and A401–2). AUA, in turn, is preceded and made possible by the original synthetic unity of apperception (o-SUA) (B133). Since what precedes and makes possible the constitutive condition of conceptual (= discursive) representation cannot itself involve concepts (discursivity), but instead must be formed entirely out of intuitions (B132), o-SUA must not only be precategorial (like AUA) but prediscursive as well (unlike AUA). It is therefore viciously circular to suppose that the categories in any way condition or ground o-SUA.
McLear concedes the basic correctness of my argument that “apperception grounds the possibility of conceptual representation, including the categories”, but maintains that it is still possible that “the activity through which the unity of apperception comes about always involves or entails categorial activity, and thus discursive activity more broadly. I take it that this position would need to be ruled out if Waxman’s aim to vindicate the Non-Discursivity Thesis is to be successful”. How my argument fails to rule out this possibility he does not explain. If the categories are concepts and concepts presuppose AUA, then the categories cannot exist until AUA does. So, if AUA cannot exist until o-SUA exists, how can not-yet-existent categories play any part in the activity originally responsible for bringing o-SUA into existence? McLear does not say and I simply do not see how they could. The same is true of discursive activity once it is admitted that by ‘discursive’ Kant always meant ‘representation by means of concepts’. For if there can be no concepts without AUA, there can be no discursive representation without AUA, and so too no ‘discursive activity’. But if AUA is preceded and made possible by o-SUA, then it is impossible for discursive activity to contribute in any way to the activity responsible for producing o-SUA, i.e. that activity must be wholly prediscursive. Thus, accepting my argument leaves McLear no defence against the charge of foisting vicious circularity on Kant by denying that Kant affirmed prediscursive, precategorial apperception.
IX. B136 note Clinches the Principal Thesis of KAIM, Part II
Numerous texts are referenced in KAIM, part II in support of my interpretation of the space and time of the Transcendental Aesthetic as having their source not only in sense but in imagination and prediscursive apperception as well. But B136n is the one I consider most important both because of its key location in the B-edition Transcendental Deduction of the Categories and because it could not be more favourable to my interpretation had I written it myself.
McLear seems to miss the point I use B136n to make in KAIM, Chapter 5-B. I claim it suffices all by itself to settle once and for all the following question: whether the prediscursive unity of all possible spaces in space and all possible times in time attributed to space and time in the metaphysical expositions of the Transcendental Aesthetic is an original synthetic unity or a unity that is non-synthetic and/or derived (‘derived’ being the term Kant contrasted with ‘original’). B136n states unequivocally and incontrovertibly that the unity of the manifold of sensibility in one consciousness, independently of all concepts (hence nondiscursively), effected by the Aesthetic’s space and time is “synthetic yet also original”. This not only confirms my claim that the unities of the Aesthetic’s space and time are original synthetic unities but also, when combined with two other things that can be confidently attributed to Kant, proves the rest of my interpretative thesis in KAIM, Chapter 4: that space and time are products of imagination and prediscursive apperception as well as sense. To wit: given Kant’s express assertion at A24–5/B39 and A31–2/B47 (echoed in B136n.) that space and time are prediscurisve, and his equally unambiguous, iterated assertion that synthesis is always an expression of spontaneity, that leaves only the spontaneity of purely aesthetic imagination and prediscursive apperception to account for the original synthetic unity of the space and time of the Aesthetic affirmed at B136n.
McLear takes issue with my reading of B136n on the ground that “the unity of consciousness that is synthetic and ‘yet […] original’ is not the unity of the pure intuitions themselves, but the unity of consciousness in their representation”. I find this puzzling. Aren’t intuitions instances of consciousness? Are the pure intuitions of space and time at the focus of the Aesthetic non-conscious? And if they were, wouldn’t that make us totally oblivious of pure space and time and everything in them? Clearly, the use of ‘intuition’ in B136n. must be understood as synonymous with ‘intuitive consciousness’.
Still, McLear wants to distinguish “in one” from “the consciousness of that one” in Kant’s assertion that “space and time and all their parts are intuitions […], not mere concepts through which one and the same consciousness is contained in many representations but many contained in one and in the consciousness of that one”. Unfortunately, he never tells us what that nonconceptual (= nondiscursive) consciousness is if it is not the intuition (= intuitive consciousness) of space and time itself; I for one haven’t a clue what else it could be. In any event, if Kant had intended a distinction between intuition and the consciousness of it, then, given the parallel construction in the sentence, wouldn’t there also have to be a distinction between “concepts” and the “consciousness contained in many representations”? Clearly, the conceptual representation is the consciousness in many representations that Kant is talking about, and it is no less clear that the intuitive representation in which many are contained is the non-conceptual consciousness in which that many are united—i.e. we are dealing with a hendiadys.
My reading of B136n is confirmed by Kant’s statement at B160n that the space and time of the Aesthetic “are first given as intuitions” only through a synthesis and unity not belonging to sense—a synthetic unity of the pure space and time intuitions that makes possible (and so must also precede) all concepts of space and time, e.g. in geometry. In line with B160n’s equation of the formal intuitions discussed there with the Aesthetic’s space and time, I read this synthetic unity as original and prediscursive as well, and consequently take the synthetic unitary space and time of B160 and B160n to be the same as the prediscursive original synthetic unity of consciousness in the intuitions of space and time affirmed at B136n (see KAIM, Chapter 5-E and -F).
X. Understanding and the Capacity for Apperception Are One and the Same
McLear denies that Kant regarded understanding as the faculty of apperception despite the fact that Kant says as much on numerous occasions. McLear’s reasoning is that apperception’s being the ground of the possibility of (i) categorial understanding (A401), (ii) understanding through concepts of objects (B137), and (iii) discursive understanding in general (B131), precludes understanding being the faculty of apperception—for “if something grounds another thing’s possibility it cannot be identical with that thing”. But this does not follow. It is no different from saying that if discursive understanding precedes and makes possible categorial understanding, then the categories cannot have their source in discursive understanding. Clearly, that is false: the categories derive from the logical functions of judgement that, along with AUA, are constitutive of discursive understanding. In the same way, discursive understanding has its source in prediscursive understanding insofar as AUA is preceded and made possible by the prediscursive o-SUA that forms out of intuitions ahead of all concepts. And one could not ask for more explicit confirmation of this reading than Kant’s statement at B133–4n that o-SUA “is the understanding itself”.
For Kant, as for Descartes before him, the understanding is, first and foremost, the faculty responsible for the representation ‘I think’. On Kant’s analysis of the ‘I think’, there are two, analytically related sides of one and the same self-consciousness: o-SUA and AUA (B133–5). In other words, the two are different representations of one and the same unity of consciousness: synthetically represented as an individual containing its manifold within it (i.e. o-SUA has/is intuitive form) vs. analytically represented as a universal containing its manifold under it (AUA has/is conceptus communis form). Thus, the fact that o-SUA unity is prediscursive does not make it any less essentially bound up with the representation ‘I think’, and so a consciousness to which the understanding’s unity is no less necessary than sense’s manifold and imagination’s synthesis (see KAIM, Chapters 5 and 9).
XI. Refuting McLear’s Mereological Refutation
McLear confined his comments to a sliver of KAIM, roughly half of Part II (Chapters 3–5) of a book with five parts and 18 chapters. This is especially problematic because he focused his comments on my treatment of pure intuitions of space and time and their relation to apperception, the full treatment of which occupies most of the book, especially Parts IV (Chapters 12–15) and V (Chapters 16–18), which are of a piece with Part II. To comment on Part II while ignoring Parts IV and V is therefore to invite misinterpretation.
A case in point is the argument in which McLear seems to place most stock: the mereological argument that supposedly proves that space and time cannot be products of synthesis. Its gist is this: space and time could only be synthetic if they were synthesised from spatial and temporal parts; but Kant was quite clear that space and time precede and make possible all their parts; therefore, Kant could not have regarded space and time as products of synthesis. Aside from ignoring the numerous texts I reference in which Kant expressly stated that space and time do involve synthesis, McLear neglects to mention that Kant’s claim that space and time precede and make possible their parts is noted in KAIM (e.g. p. 91) and factored into my interpretation. So far as I am concerned, it proves nothing either way about the synthetic character of space and time. Kant distinguished many different kinds of synthesis in the Critique and I fully agree with McLear that the synthesis responsible for space and time is not a synthesis of space and time wholes from space and time parts. The latter species of synthesis is a synthesis of composition of a kind that, on my interpretation, is based as much on the categories of quantity and quality as it is on the prediscursive pure space and time intuitions, making it a discursive rather than a purely aesthetic synthesis, and therefore precluding it from being the synthesis responsible for the purely aesthetic, prediscursive, precategorial space and time intuitions that Kant set out to expound and validate in the Aesthetic.
Anyone who has read KAIM, Chapter 15 knows that I analyse the transcendental synthesis of the manifold of purely aesthetic space and time conformably to the pure concepts of the understanding in unprecedented detail. They would also know that in the absence of this transcendental synthesis, I consider the manifolds of purely aesthetic space and time to be completely undifferentiated and indeterminate, even to the point of being totally devoid of limits of every kind (points or moments, lines or durations, planes), magnitude (numerical, extensive, continuous, discrete), situational order (immediately adjacent or remote, so far remote along such-or-such a route) and sequential order (determinately before or after, determinately so much before or after). Lacking all these, however, implies being devoid of differentiable, determinable parts of any kind, and ipso facto precludes the possibility of any synthesis of wholes from parts.
What remains when all discursive synthesis is precluded, so that the only synthesisable representations of space and time left are intuitions that contain nothing more than a completely undifferentiated, indeterminate manifold? The purely aesthetic, prediscursive synthesis KAIM credits with producing space and time is the one Kant termed “synthesis of apprehension in intuition” (note how he titled it—its products are intuitive, not discursive). As characterised by Kant, apprehension suffices only to represent the manifold of sensibility as a manifold (A99), but no more: a bare manifold of perceptions encountered “scatteredly and singly” (A120), hence not yet ordered or related in any way, even subjectively via association in reproductive imagination, much less by means of concepts and judgements in recognitive synthesis or transcendental synthesis in accordance with pure concepts of the understanding. Indeed, so psychologically primitive is the synthesis of apprehension that, according to Kant, all previous psychologists had attributed it to sense rather than to imagination (A120n). Thus, apprehension is the perfect candidate for a synthesis able to yield nothing more than the completely undifferentiated, indeterminate manifold that KAIM equates with the manifold of the purely aesthetic space and time intuitions—the manifold that constitutes the prediscursive input for the discursive transcendental synthesis whose output includes the kind of whole-part mereological relations exemplified by extensive magnitudes and, more abstractly, by numbers.
It is precisely because Kant shifted apprehension from sense to imagination that he could maintain, in opposition to all preceding psychologists, that receptivity never synthesises and that products of syntheses always have to be made, i.e. are always expressions of spontaneity, never givens of sense. Apprehension is the absolute minimum of synthesis, sufficient only for the representation of the manifold as a bare (undifferentiated, indeterminate) manifold of scattered and single perceptions. That is what makes the a priori version of this synthesis the obvious candidate for the synthesis responsible for synthesising purely aesthetic, prediscursive space and time. And Kant says as much when he tells us that “without it, we would be able to have a priori neither representations of space nor of time, for these can be produced only through the synthesis of the manifold that sensibility offers in its original receptivity” (A99–100).
Clearly, no mereological objection can be raised to KAIM’s attribution of space and time to a precategorial, prediscursive, prereproductive synthesis in which the manifold is met with so scatteredly and singly that organisation into parts and wholes is as impossible as geometrical organisation generally.
XII. Apprehension, Reproduction, Customary Association
McLear contends (1) that I am mistaken to assert that preassociative, prediscursive unity of sensibility (prediscursive apperception) is presupposed by inter-sensory modal reproduction, association and comparison, and am certainly wrong to do so in the case of intra-sensory modal association. He also maintains (2) that I am mistaken to hold that sensibility is required to be a multi-sensory consciousness, as if it were not possible for sensibility to exist with a single sensory modality only. And (3) taking me to assert that sensibility has to be conceived as I propose for there to be individuation of particulars by spatio-temporal position, McLear cites Strawson to make the case that such individuation is completely independent of any particular way of conceiving sensibility but instead depends on the general notion of a particular and the metaphysical and epistemological conditions of particulars’ individuation.
I do not assert (1) in the case of the unity of external sensibility effected by space, but only of the unity of internal sensibility effected by time, and I do not assert what I am supposed to in (2) or (3) at all.
Everything I said in response to McLear’s mereological refutation applies to (3) as well. In KAIM, I attribute the individuation not only of particular objects but of the spaces and times they occupy to understanding’s transcendental synthesis, not to sensibility. I analyse their individuation as a three-stage categorial-discursive synthesis, starting with the differentiation and determination of the manifolds of pure space and time via pure concepts of the understanding in transcendental synthesis (KAIM, Chapter 15), proceeding to the differentiation and determination of the physical realities corresponding to the matter of appearances via transcendental schematism (Chapter 16), and concluding with the subsumption of the threefold empirical synthesis (apprehension–reproduction–recognition) under transcendental schemata in transcendental judgements (Chapters 17–18). By contrast, the manifolds comprised in the unity of sensibility constituted by purely aesthetic, prediscursive space and time are repeatedly characterised in KAIM as completely undifferentiated and indeterminate, and so entirely insufficient for objective individuation of spaces and times or the particulars in them. Purely aesthetic space and time instead suffice only for the kind of subjective (non-objective, non-cognitive) individuation that is wholly dependent on a posteriori consciousness of particular sensations, e.g. the expanse of blue sky, the sticky prickly surface, the pain that succeeded his tumble.
As for (2), since KAIM neither asserts nor implies that sensibility is essentially multi-sensory, it is no surprise that McLear does not offer any evidence for his claim that it does. KAIM, Part II, like the Transcendental Aesthetic of the Critique itself, is concerned with the multi-sensory sensibility of apperception-capable human and human-type minds. In it, I argue that Kant defended the view that incommensurable fields of heterogeneous sensations can only be united in a single consciousness (unity of sensibility) insofar as intuition permits them to be exhibited by nonsensational homogeneous appearances. One may agree or disagree with this, but in no way can it be construed to imply the impossibility of creatures with only a single sensory modality.
As for (1), I think it important to distinguish the unity of sensibility constituted by space (unity of outer sensibility) from that constituted by time (unity of inner sensibility). I regard Kant’s account of inter-modal spatial sensibility in terms of the prediscursive, preassociative pure consciousness of space produced via apprehension only as an alternative to Berkeley’s associationist account of sensible spatiality. I never claim, either in KEUU or KAIM, that pure consciousness of space is presupposed by association, whether in Berkeley’s theory of vision, Hume’s account of human nature, or Kant’s treatment of association.
That association does presuppose a prior consciousness is, however, indisputable. How could a creature associatively relate A to B if one or the other were preassociatively absent from its consciousness? Whether in sensation or thought, they must both already be present in its consciousness in unassociated form before it can consciously associate them (for Berkeley, Hume and Kant, consciousness of relation always requires an act of the mind). Kant’s name for this prior consciousness is synthesis of apprehension in intuition: it produces the perceptions (A120n.) that constitute the input of reproductive imagination, which then proceeds to order and relate these scattered, single (A120) perceptions via subjective rules of association (A121). What differentiates Kant from Berkeley and Hume in this matter is not the affirmation of preassociative (pre-reproductive) synthesis of apprehension but rather Kant’s being the first to attribute apprehensive consciousness to imagination rather than sense (A120n.; and to spontaneity rather than receptivity at A97).
Kant did however maintain that association presupposes time (e.g. A98–9). This is easiest to see in the case of customary association. Associative customs can only be formed insofar as there is consciousness of the frequent and constant occurrence or co-occurrence of perceptions. Consciousness of their frequency and constancy in turn requires consciousness of perceptions as events in a single, unified linear time in which each perception is objectively before or after such-or-such other perception and objectively so much before or after it. According to KAIM, the representation of such a time is possible only through the transcendental synthesis of the manifold of purely aesthetic time conformably to pure concepts of the understanding. Thus, customary association not only presupposes the prediscursive unity of inner sensibility constituted by the pure time intuition but the discursive unity of objective experience constituted by categorial transcendental synthesis as well. That, at any rate, is how KAIM, Parts IV–V cash out Kant’s claim at A113–14 and A121–2 that the possibility of (customary) association is grounded on apperception. Consequently, any creatures lacking the capacities requisite for transcendental synthesis that manifested effects similar to those of customary association in us would have to achieve them by entirely different means (cf. Anth, AA 7:397, cited in Section VI.4 above).
Custom aside, I also provide an argument to show that association itself, intra- no less than inter-modal, is only possible given pure intuition of time (unity of internal sensibility). Its focus is not Berkeley’s theory of vision but what I called “Hume’s quandary” in KEUU, Chapter 3 and revisit at various points in KAIM. The gist of my argument is as follows. In the well-known Treatise appendix on personal identity, Hume expressed his belated recognition that the problem of how successive perceptions come to be united in our thought or consciousness cannot be solved associatively but only by a consciousness in which successive perceptions are united ahead of all association, reproduction, comparison, or anything else that goes beyond bare apprehension. Hume could see no way to explain such a consciousness other than by having recourse to metaphysical notions of an enduring mind-substrate of perceptions or real (not merely customary) causal connections between distinct perceptions—solutions forbidden by his unrenounceable sceptical principles. I argue in KEUU/KAIM that Kant was able to avoid Hume’s quandary by explicating the preassociative unity of successive perceptions in internal intuition purely psychologically, in terms of the unity of inner sensibility effected by the pure time intuition: since succession exists only in and through that intuition, no succession of perceptions (appearances) can fail to be united in the intuitive consciousness of pure time. Moreover, because the pure time intuition is generated by productive imagination’s synthesis of apprehension, this preassociative unity of all inner appearances in time no more requires reference to metaphysical substrates or causes than associative imagination does in Berkeley’s account of how nonspatial visual sensations acquire spatial meaning from tactual sensations. Finally, since time (succession) for Kant is an intuition of imagination rather than anything given in sensation, only nonsensational appearances can ever be successive; preimaginative sensations (i.e. outer and inner affections of sense), by contrast, are no more temporal than they are spatial. Thus, in the case of sensations, Kant had no succession to explain, hence no need to explain the unity of successive sensations in consciousness, and so was never in any danger of falling into the quandary of having to choose between his unrenounceable critical principles and dogmatic metaphysical substrates or causes.
Acknowledgements: I want to express my grateful appreciation to Dennis Schulting, who conceived and organised the foregoing discussion of my book, and to John Callanan and Colin McLear for their excellent comments and criticisms.
Received: 30 October 2018.
 In addition to KEUU and KAIM, they are Waxman (1991) and (1994).↩
 Hume is the fountainhead of psychologism (the group of 19th century German philosophers for whom the term ‘psychologism’ was originally coined claimed to be following in his footsteps). Hume’s psychologism, however, must be understood so that everything in it applies not only to human but to non-human animal minds as well. Thus, as I interpret Hume in KEUU (Chapters 1–4 and 15–20), there is no place in his psychologism for epistemology or the truth conditions of sentences (language being for Hume dependent on convention, and so a product not of human nature but human artifice)—though it does of course have the consequence of restricting the scope of knowledge to all and only what is knowable through consciousness-conditioned representations. Much the same is true of Kant’s a priori psychologism: it primarily concerns non-linguistic representation (the analytic of understanding), and only secondarily the limits to knowledge implied by our having only consciousness-conditioned representations of objects with which to think them.↩
 Without claiming originality (the reading arguably goes back at least to Hegel), I first published on this way of interpreting Kant’s understanding of the relation of general logic to apperception in a 1995 article (Waxman 1995).↩
 This is in line with Kant’s insistence that his philosophy is a system that needs to be approached so that each of its parts is understood through the whole no less than the whole through the parts.↩
 Only if Riemann were inconsistent with Euclid could it be argued that my version of Kant faces a problem, on the ground that necessary, universal synthetic a priori truths should never conflict. But since Riemann, as generally understood, subsumes Euclid as one case among other, non-Euclidean cases, no conflict exists.↩
 Obviously, Kant’s metaphysics of nature is Newtonian, but while a priori, metaphysics of nature differs from transcendental philosophy in not being pure, i.e. it incorporates empirical concepts and depends on certain Grunderfahrungen (fundamental experiences). I argue in KAIM that a metaphysics of nature written in Ancient Greece would have concerned itself with the empirical concepts and fundamental observations that occupied philosophers like Aristotle, while one written now would focus on the concepts and observations specific to relativity and quantum theory.↩
 This is another instance of one of the most important and original theses elaborated in KAIM being overlooked.↩
 For example, if the content of the predicate of an affirmative categorical judgement is already contained in the content thought in the subject concept (e.g. “Gold is metallic”), then the judgement falls under the principle of identity and is analytically true, but if its content makes the content of the subject concept quite literally unthinkable (e.g. “Gold is non-metallic”), then the judgement falls foul of the principle of contradiction and is analytically false.↩
 Since I had already considered Kant’s views on animal consciousness in some detail in Kant’s Model of the Mind, I saw no need to do so again in KAIM.↩
 This includes references to texts cited and analysed in Waxman (1991), which was devoted to the imagination/synthesis portion of the question. KAIM, Part II focuses more on the apperception/unity component of pure space and time.↩
 McLear seems to interpret synthesis of imagination as intellectual in character, but there is abundant textual evidence to demonstrate that Kant regarded the imagination as the faculty of intuition and as much a part of sensibility (though not receptivity!) as sense itself: see e.g. KAIM, p. 102 (having already made the full textual case in Kant’s Model of the Mind, KAIM, Part II presents only a textual sampling, but by no means an inconsiderable one).↩
 I can see no textual warrant whatsoever for the alternative reading of B133–4n McLear proposes in a footnote, nor does he attempt to provide one.↩
 Since Kant elsewhere attributes space and time to productive imagination, I refer them to imagination under that denomination as well: see KAIM, pp. 113–14.↩
Waxman, W. (1991), Kant’s Model of the Mind. A New Interpretation of Transcendental Idealism (Oxford: Oxford University Press)
——— (1994), Hume’s Theory of Consciousness (Cambridge: Cambridge University Press).
——— (1995), ‘Kant on the Possibility of Thought’, Review of Metaphysics 48(4): 809–59.
——— (2005), Kant and the Empiricists: Understanding Understanding (Oxford: Oxford University Press).
——— (2019), A Guide to Kant’s Psychologism via Locke Berkeley Hume and Wittgenstein (London: Routledge).
© Wayne Waxman, 2018.
Wayne Waxman is the author of Kant and the Empiricists: Understanding Understanding (Oxford UP, 2005), Hume’s Theory of Consciousness (Cambridge UP, 1994), and Kant’s Model of the Mind. A New Interpretation of Transcendental Idealism (Oxford UP, 1991). His A Guide to Kant’s Psychologism via Locke Berkeley Hume and Wittgenstein is forthcoming from Routledge in 2019. He is retired and lives in New Zealand.