List of Abbreviations of Kant’s Works
ApH Anthropologie in pragmatischer Hinsicht, Ak 7 (1798)
Anthropology from a pragmatic point of view
Bew Der einzig mögliche Beweisgrund zu einer Demonstration des Daseins Gottes, Ak 2 (1763)
The only possible argument in support of a demonstration of the existence of God
B Briefwechsel, Ak 10 (1747–1788)
Correspondence
BBM Bestimmung des Begriffs einer Menschenrasse, Ak 8 (1785)
Determination of the concept of a human race
DR Danziger Rationaltheologie in Vorlesungen über Metaphysik und Rationaltheologie, Ak 28 (1783/1784)
EaD Das Ende aller Dinge, Ak 8 (1794)
The End of All Things
FM Welches sind die wirklichen Fortschritte, die die Metaphysik seit Leibnitzens und Wolf’s Zeiten in Deutschland gemacht hat? Ak 23 (1793/1804)
What real progress has metaphysics made in Germany since the time of Leibniz and Wolff?
GTP Über den Gemeinspruch: Das mag in der Theorie richtig sein, taugt aber nicht für die Praxis, Ak 8 (1793)
On the common saying: This may be correct in theory, but it is of no use in practice
IaG Idee zu einer allgemeinen Geschichte in weltbürgerlicher Absicht, Ak 8 (1784)
Idea for a universal history with a cosmopolitan aim
KrV Kritik der reinen Vernunft, Ak 3 (1781, 1787)
Critique of pure reason
KpV Kritik der praktischen Vernunft, Ak 5 (1788)
Critique of practical reason
KUEE Erste Einleitung in die Kritik der Urteilskraft, Ak 20 (1789)
First Introduction to the Critique of the Power of Judgement
KU Kritik der Urteilskraft, Ak 5 (1790)
Critique of the Power of Judgement
LM Vorlesungen über die Metaphysik, Ak 28 (1760–1790)
Lectures on Metaphysics
LD Logik Dohna-Wundlacken, Ak 24 (1790)
Logic Dohna-Wundlacken
LJ Jäsche Logik, Ak 9 (1800)
Jäsche Logic
MAM
Mutmaßlicher Anfang der Menschengeschichte, Ak 8 (1786)
Conjectural beginning of human history
MdS Metaphysik der Sitten, Ak 6 (1797)
Metaphysics of morals
MM Metaphysik Mrongovius, Ak 29 (1782–1783)
Metaphysics Mrongovius
Nachlass Reflexionen aus dem Nachlaß, Ak 14–23
Notes and fragments, unpublished remains
nevT Von einem neuerdings erhobenen vornehmen Ton in der Philosophie, Ak 8 (1796)
On a Recently Prominent Tone of Superiority in Philosophy
Ped Immanuel Kant über Pädagogik, Ak 9 (1803)
Lectures on pedagogy
RP Religionslehre Pölitz, Ak 28 (1817)
Lectures on the philosophical doctrine of religion
Rel Religion innerhalb der Grenzen der bloßen Vernunft, Ak 6 (1793)
Religion within the boundaries of mere reason
SdF Der Streit der Facultäten, Ak 7 (1798)
The conflict of the faculties
TPP Uber den Gebrauch teleologischer Prinzipien in der Philosophie, Ak 8 (1788)
On the use of teleological principles in philosophy
VA Vorlesungen über Anthropologie, Ak 25
Lectures on anthropology
VRM Von den verschiedenen Rassen der Menschen, Ak 2 (1775, 1777)
Of the different races of human beings
WiA Beantwortung der Frage: Was ist Aufklärung? Ak 8 (1784)
An answer to the question: What is enlightenment? x List of Abbreviations of Kant’s Works
WhDO Was heißt: Sich im Denken orientiren? Ak 8 (1786) What does it mean to orient oneself in thinking?
WL Wiener Logik, Ak 24 (1780)
Vienna Logic
ZeF Zum ewigen Frieden: Ein philosophischer Entwurf, Ak 8 (1795) Toward perpetual peace: A philosophical sketch
These references are to Kant’s Gesammelte Schriften. Ausgabe der Preußischen (later Deutschen) Akademie der Wissenschaften (Berlin Georg Reimer, later Walter de Gruyter, 1902–)
Unless otherwise noted, all translations follow those in The Cambridge Edition of the Works of Immanuel Kant, edited by Paul Guyer and Allen W. Wood (New York: Cambridge University Press, 1992–). Slightly amended translations are signalled in the respective footnotes.
Acknowledgements
I started working on this book a very long time ago, more than 20 years. I was in the middle of my Philosophy degree at the University of Rome ‘La Sapienza’ and, after a couple of years studying formal logic, I turned to the history of philosophy. I was fascinated by German idealism and, for a series of personal and political reasons, I was also interested in Marx, and in Marx’s critique of religion. Yet when I started researching Marx, I realized that to understand him properly, I had to master Hegel. And when I turned to Hegel, I thought his texts were prohibitively difficult to grasp, unless you understood what Kant had been up to, especially in his Critique of Judgment which was widely thought to offer the ‘solution’ to the problem of the relation between nature and freedom. I therefore decided to write my dissertation on systematic unity in Kant’s third Critique. But in the process of analysing the development of Kant’s theory of judgment and its relation to the rest of Kant’s writings, I stumbled on the only early pages in which Kant discusses explicitly the problem of the unity of the system: The Architectonic of Pure Reason. This seemed like an important, deep, and complicated section of the first Critique, and the fact that it was so obscure and that there was so little written on it (even less when I started than there is now) meant that the project of understanding what Kant tried to do in the Architectonic took on a life of its own.
My thoughts and my relationship to Kant have developed along the way, but I think it is fair to say that everything I believe, about philosophy, science, morality, history, and politics and about the relation between these, has its roots in the Architectonic and in my interpretation of what Kant tried to do in it. None of these thoughts would be what they are without the inspiring conversations, challenging discussions, and intelligent commentary of my friends and mentors in Rome, and I am especially grateful to Renato Caputo, Filippo Gonnelli, Mario Reale, and Paola Rodano. This project owes them more than I can say.
The project has had a very long gestation, so long that I wondered more than once if it would ever come to an end. The fact that it happened is also to the merit of a number of friends and colleagues who shared with me their enthusiasm for Kant and their knowledge of his work. I am especially
grateful to Sorin Baiasu, Luigi Caranti, Francesco Cori, Silvia De Bianchi, Karin De Boer, Katrin Flikschuh, Rainer Forst, Paul Guyer, Stefan Gosepath, Pauline Kleingeld, Michela Massimi, Jennifer Mensch, Sasha Mudd, Peter Niesen, Alessandro Pinzani, Gennaro Sasso, Andrew Stephenson, the late Francesco Valentini, Marcus Willaschek, Garrath Williams, Howard Williams, and Tamara Jugov for helping with bibliographic suggestions, for reading and commenting on different parts of the book, and for many stimulating conversations on the topic. I am also very grateful to Bob Goodin for his ongoing support of my work.
The manuscript on which the book is based was the subject of an intense one-day workshop at the LSE, and I would like to thank the Government Department for supporting the workshop and especially Angela Breitenbach, Luigi Filieri, Gabriele Gava, Jakob Huber, Sofie Møller, Paola Romero, and Thomas Sturm for participating and giving incredibly helpful and constructive suggestions. I am also grateful to my OUP editor Peter Momtchiloff for having confidence in the project, to three anonymous reviewers for their excellent comments, to Marta Lorimer for her editorial assistance, and to Rainer Forst, Sandra Palermo, and Garrath Williams, for reading a full draft.
The book benefitted from funding from the Istituto Italiano di Studi Storici in Naples, from the Alexander von Humboldt Stiftung, from a Leverhulme Prize, and from a ‘Kant in South America’ Horizon 2020 grant from the European Commission. I am very grateful to these institutions for enabling me to conduct the research on which the book is based.
My family, Arbien, Rubin, Hana, Jonathan, Doli, Lani, and Noana are an unfailing source of love and support to which I owe more than it would be appropriate for a Kantian to acknowledge.
To Paola Rodano and Mario Reale, I am especially grateful for making me believe in philosophy when I started this journey, for (more than once) making sure I had the material means to continue engaging with the world of ideas, and for being with me at every step along the way. This book is dedicated to them.
Constructing Reason
This book is about the unity of reason in the Critique of Pure Reason. It tries to explain why the unity of reason is necessary, how Kant defends it, and why the project fails. Its main argument is that the unity of reason is grounded on a transcendental principle of purposiveness that is essential to the systematic integration of reason’s theoretical and practical uses, but also a threat to the separation of critique from metaphysics that motivates Kant’s project. Authors who worry about the role of the unity of reason in the first Critique focus either on the contribution of purposiveness to the systematic unity of theoretical cognitions or on its contribution to the realization of the practical ends of reason. They hardly reflect on how the first informs the second, but also depends on it, and on what the two taken together tell us about the fate of the critical project as a whole.
This is not surprising. The only part of the Critique of Pure Reason in which Kant examines the organic integration of the different uses of reason is The Architectonic of Pure Reason. This also happens to be one of the densest, obscure, and at times outright impenetrable texts in Kant’s entire body of published work. On reading it, it is difficult not to feel sympathy for the majority of commentators whose frustration with the text seems to have historically led to a massive call to boycott it. The result is that after hundreds of thousands of pages written on Kant’s systematic project and almost 250 years from the publication of the first Critique, those engaging explicitly with the Architectonic are only a handful, and those who do so in a charitable way are even fewer.
In exploring the role of the principle of purposiveness for Kant’s analysis of the unity of reason, this book offers an interpretation of the Architectonic of Pure Reason that restores its centrality to Kant’s philosophical project. It argues that the Architectonic is a significant and unique text for understanding why the unity of reason is necessary, what role the principle of purposiveness plays in integrating the theoretical and practical uses of reason, and
how engaging with Kant’s challenge may be relevant to reflect on the problem of systematic unity in philosophy more generally. Even though Kant’s defence of the unity of reason in the first Critique fails because it threatens Kant’s own separation of critique from metaphysics, that failure is productive. Unlike the vast majority of commentators, who have dismissed the Architectonic outright, I try to show that its focus on unified reason is crucial to shed light on the development of some of Kant’s most important ideas. These include but are not limited to: the passage from the system of nature to that of freedom; the relation between faith and knowledge; the philosophical defence of progress in history; and the role of religion.
As is well known, these questions have significantly shaped the subsequent German philosophical tradition, from the initial reactions of Jacobi, Reinhold, Schulze, and Maimon, to the partial assimilation of their analyses in the idealism of Fichte or Hegel, to Marx’s Critique of Hegel’s Philosophy of Right. 1 At the heart of their concerns is always the same problem: where does the authority of reason come from? In what relationship does it stand to nature? How does reason order the different inferences it makes about the world? They all boil down to an effort not only to explain the relationship between different philosophical claims in the realms of science, morality, politics, and religion, but also how to understand their purpose, the values they promote. Kant presents his defence of the unity of reason in the Architectonic as a further elaboration of three fundamental questions: ‘What can I know? What should I do? What may I hope?’ (KrV, A 805, B 833; 677). Together they converge on a fourth one, which, as Kant argues, animates philosophy as a whole: ‘was ist der Mensch?’ (LM, 28: 533–534; 301; LJ, 25; 538).
What is the human being? This book suggests that Kant’s answer to this question is tied to a particular account of reason, one that stresses its purposive character. But as the following pages go on to show, the concept of purposiveness that Kant endorses in the first Critique is a notion of purposiveness as design, quite different from the notion of purposiveness as normativity that will become central to his later works. In the first case, purposiveness as design, the relationship between reason and nature, is anchored to the idea of God. In the second case, purposiveness as normativity, it is anchored to the concept of reflexive judgment, and grounded on
1 For a discussion of this legacy, see Beiser, Frederick C., The Fate of Reason: German Philosophy from Kant to Fichte (Cambridge, MA: Harvard University Press, 1987). I have discussed the comparison with Hegel and Marx in Ypi, Lea, ‘On Revolution in Kant and Marx’, Political Theory, vol. 42 (3) (2014), 262–287.
transcendental freedom. God remains part of the system but plays an increasingly marginal role; one that paves the way for successive authors, such as Hegel and Marx, to turn to a philosophy of history which eliminates the need for it altogether.
In The Architectonic of Reason, the principle of purposiveness, which is connected to the defence of the ideas of reason, plays a central role in the project of unification. But as I also try to show, only an account of purposiveness rooted in transcendental freedom can remain compatible with the critical commitments laid out in the earlier parts of Kant’s work. Since in the first Critique that account of freedom is not available, Kant’s justification of purposiveness remains difficult to isolate from the previous metaphysical tradition. In particular, Kant finds it impossible to come up with a notion of purposiveness that departs sharply from the way in which his seventeenthand eighteenthcentury predecessors grounded considerations about the order of nature on assumptions of intelligent design. This leaves Kant with a problem. Either the project of integrating the different uses of reason is condemned to failure, or one sketches an alternative defence of purposiveness, which is free from dogmatic assumptions about the presence of order in nature. Understanding this transition has important implications both for Kant’s later work, and for its reception in the subsequent German philosophical tradition. After Kant’s reflexive endorsement of the principle of purposiveness, the philosophical theories of history that defined the nineteenth century could only share Kant’s critical commitments. If they returned to metaphysics, it was the critical metaphysics that Kant had hoped to ground.
The Architectonic of Pure Reason deserves to be taken seriously because it is the only part of the first Critique to explicitly engage with the unity of reason, and through which we understand the centrality of a transcendental principle of purposiveness for that project. But it also helps us understand better the only form that assumptions about the order of nature need to take so as to escape the fate of dogmatic metaphysics. Although the project in the end fails, that failure is instructive. The Architectonic of Pure Reason contains both the solution and the riddle to the problem of the unity of reason. Engaging with this section by integrating its findings in Kant’s larger philosophical system helps us illustrate the evolution of the principle of purposiveness, and understand the revolutionary implications of its separation from the idea of intelligent design which characterizes Kant’s later work.
To see the relevance of Kant’s architectonic project, we must begin at the beginning, with the pages of the Critique of Pure Reason which highlight the importance of the unity of reason for our understanding of Kant’s overall project. This is first brought out through a curious, if unsurprising, metaphor. The sum of reason’s theoretical cognitions are compared to the material necessary for the construction of a building, whose type, solidity and height Kant claims to have assessed in the first part of this work. Even though reason initially aspired to build a majestic tower reaching the sky, the material discovered, Kant argues, was only enough for a house, sufficient for the satisfaction of human needs. The remaining task of the Critique, that of its Doctrine of Method, is to delineate the plan according to which that construction should be completed (KrV, A 707, B 735; 627).
Kant’s methodological guidelines are introduced here through an implicit but clear reference to the myth of the tower of Babel. He compares his own enterprise with earlier accounts of reason whose ambitions exceeded the cognitive material at their disposal, failing, as a result, to place philosophy on solid grounds. Taking stock of their failures must be a warning sign for all philosophical projects which end up overcoming human cognitive capacities. Yet, since a unitary account of reason is also necessary for the satisfaction of its distinctive needs, the challenge must be taken up in the rest of the first Critique. Or so Kant explains.
The use of metaphors related to construction in introducing issues of philosophical method was very common for philosophers writing in the seventeenth and eighteenth centuries. To mention but the most prominent example, one of the opening chapters of Descartes’ Discourse on the Method adopts the metaphor of the building to explain how the author felt the need to depart from the scholastic method of enquiry and replaced it with a more radical assessment of the first principles of human knowledge. The method of the philosopher, Descartes argues, is similar to that of the architect. An architect aiming to build a house on solid ground must explore the soil, assess the terrain, and discard any material that obstructs the construction. In a similar way, the scholar that wants to place reasoning on new and secure grounds must start by ensuring that the territory in which she is about to venture has been checked beforehand, that all superfluous material has been discarded and that obstacles have been removed prior to laying its foundations.2
2 Descartes, René, ‘Discourse on the Method’ (1644), in The Philosophical Writings of Descartes, transl. by J. Cottingham, R. Stoothof, and D. Murdoch (Cambridge: Cambridge University Press) 1984, vol. 1, 111–176, at 116 ff.
Admittedly, Descartes insists, this is not the kind of enterprise with which either philosophers or architects would frequently associate themselves. Even if they did, their activity rarely would take the form of a radical destruction of what has previously been achieved. Yet, we occasionally do witness efforts to replace individual constructions with more appropriate buildings when the foundations are weak or the houses run the risk of falling apart. Thus, even if it might sound unreasonable to destroy a whole system so as to build it again from scratch, it may still make sense for a philosopher, as a matter of personal ethics, to suspend judgment on speculative matters and try to reexamine the beliefs that are being held.3
Kant’s endorsement of the construction metaphor to explain the relevance of methodological considerations in the critique of reason is continuous with this tradition, in particular as mediated through the writings of Leibniz and Wolff. The former emphasizes how the work of a philosopher who wants to justify the connection of different elements within a coherent system of cognitions is similar to that of a constructor. Faced with the demand to construct a building in territory made of unreliable, dusty material, that constructor ought to dig deeper until a more solid foundation is found, Leibniz argues.4 Likewise, Wolff compares the methodological task of the philosopher to that of an architect who uses parts of plans from previous and existing buildings to construct his own one in conformity with the principle of sufficient reason.5
Yet in the Doctrine of Method and elsewhere, Kant’s redeployment of the architectonic metaphor revisits the previous metaphysical tradition in a way that is also profoundly innovative. To see this innovation, it is important to refer to the unique nature of the defence of reason in the first Critique,
3 Ibid. 117.
4 ‘Quemadmodum in loco sabuloso edificium molienti continuanda fossio est, donec solidam rupem firmave fundamenta offendat [. . .] ita ad humanae scientiae Elementa constituenda desideratur punctum aliquod fixum, cui tutò inniti atque unde secure progredi possimus.’ See Leibniz, Gottfried Wilhelm, Opuscules et fragments inédits de Leibniz. Extraits des manuscrits de la Bibliothèque royale de Hannovre, edited by L. Coutourat (Paris: Alcane, 1903), 401. The influence of Leibniz is missed by Paula Manchester in her otherwise excellent reconstruction of the historical roots of Kant’s construction analogy in the Doctrine of Method, see Manchester, Paula, ‘Kant’s Conception of Architectonic in Its Historical Context’, Journal of the History of Philosophy, vol. 41 (2) (2003), 187–207.
5 See Wolff, Christian, Vernünftige Gedanken von Gott, der Welt, und der Seele der Menschen, auch allen Dingen überhaupt, zu besserem Verstande und bequemerem Gebrauch derselben (Frankfurt am Main: Andrea Verlag, 1724), 246–251 and for a further discussion Manchester, ‘Kant’s Conception of Architectonic in Its Historical Context’, cit. 199.
engaged in a twofold struggle: against dogmatism and against scepticism.6 Unlike Descartes and others, Kant’s defence of reason and his own discourse on the method do not precede the collection of the materials necessary to the critical enterprise; they follow it. Moreover, while the constructive task is for Descartes a solitary one, necessary to the philosopher’s individual engagement with his own beliefs and errors, in Kant it is the result of a collective and cumulative effort.7 Finally, but importantly, when it comes to providing practical rules, Descartes promises to simply accept and comply with existing norms and conventions. The development of a moral theory is not even contemplated in his Discourse on the Method. In the case of Kant, the ends of reason are crucial to the direction (and the plan) that should be taken by the whole critical enterprise.
These important differences, together with Kant’s vindication of reason and the relevance of method to the accomplishment of that task, are widely recognized and celebrated.8 Kant’s own discours de la méthode, it is often said, points towards the construction of a process rather than the establishment of a firm product. The Critique of Pure Reason neither proves the eternal validity of any metaphysical proposition nor concedes to the relativist that everything is therefore uncertain. On the contrary, the authority of reason is asserted by placing it at the heart of a constructive project which is recursive and public in character. The coherence of its principles is established by going back and forth in the process of assessing human knowledge and confronting its cumulative results with an ongoing conversation based on rules that everyone can in principle endorse.9 The unity of reason is
6 See for an influential discussion, O’Neill, Onora, Constructions of Reason (Cambridge: Cambridge University Press, 1989), 3–27 and ‘Vindicating Reason’, in The Cambridge Companion to Kant, edited by P. Guyer (Cambridge: Cambridge University Press, 1992), 280–308.
7 See on this point also O’Neill, Constructions of Reason, cit. and Yovel, Yirmiyahu, Kant and the Philosophy of History (Princeton, NJ: Princeton University Press, 1980).
8 See for booklength treatments Ferrarin, Alfredo, The Powers of Pure Reason: Kant and The Idea of Cosmic Philosophy (Chicago, IL: University of Chicago Press, 2015); Fugate, Courtney, The Teleology of Reason: A Study of the Structure of Kant’s Critical Philosophy (Berlin: De Gruyter, 2014); Konhardt, Klaus, Die Einheit der Vernunft. Zum Verhältnis von theoretischer und praktischer Vernunft in der Philosophie Immanuel Kants (Königstein: Forum Academicum, 1979); Neiman, Susan, The Unity of Reason: Re-Reading Kant, (New York: Oxford University Press, 1994); and Nuzzo, Angelica, Kant and the Unity of Reason (West Lafayette, IN: Purdue University Press, 2004).
9 See especially O’Neill, Constructions of Reason, 4–15 and O’Neill, Onora, ‘The Public Use of Reason’, Political Theory, vol. 14 (4) (1986), 523–551. See also for a discussion Deligiorgi, Katerina ‘Universalisability, Publicity, and Communication: Kant’s Conception of Reason’, European Journal of Philosophy, vol. 10 (2) (2002), 143–159.
therefore considered founded on moral or even political grounds.10 Once we understand the project in those terms, we can see what enables Kant to complete the critical project of foundation of metaphysics as a science in the first Critique.
The virtue of recent constructivist interpretations of the first Critique has been to direct its analysis away from the interest in the purely theoretical dimensions of critical philosophy into an integrated account of the unity of reason, which incorporates its practical interests. But those interpretations often read the first Critique backwards, in the light of what we know about the nature of practical reason based on Kant’s successive works, rather than on the basis of what the Critique itself has to say about the systematic unity of knowledge and the role of the practical interests of reason. This, in itself, is no major flaw: the aims of these interpretations are often reconstructive rather than exegetical, more narrowly applied to metaethics, and reluctant to endorse Kant’s metaphysics.11 My hope, however, is to show that an interest in the development of Kant’s architectonic, and a contextualized analysis of the principle of purposiveness that lies at its basis, helps us develop an account of reason that is not only compatible with the aims of several constructivist reinterpretations but also potentially useful to illuminate the contribution of a properly reformulated Kantian metaphysics to (at least some versions of) their project.12 While my method here is clearly more textual than that of many constructivist interpreters, our shared interest is in Kant’s vindication of reason and its ability to address the twin charges of dogmatism and scepticism. But for that vindication to succeed, it is instructive to engage with Kant’s trajectory, his faux pas, his hesitations and his breakthroughs. And while the Doctrine of Method is an essential starting point, it is important to understand why Kant appeared dissatisfied with
10 See the discussion of this issue in Wood, Allen, ‘Constructions of Reason: Explorations of Kant’s Practical Philosophy’, The Philosophical Review, vol. 101 (1992), 647–650, at 648.
11 For some of the most influential accounts, see, for example, Rawls, John, ‘Kantian Constructivism in Moral Theory’, The Journal of Philosophy, vol. 77 (9) (Sep. 1980), 515–572; O’Neill, Constructions of Reason, cit. and O’Neill, Onora, ‘Constructivisms in Ethics’, Proceedings of the Aristotelian Society, vol. 89 (1) (1989), 1–17; Hill, Thomas E., Dignity and Practical Reason in Kant’s Moral Theory (Ithaca, NY: Cornell University Press, 1992); Herman, Barbara, The Practice of Moral Judgment (Cambridge, MA: Harvard University Press, 1993); Korsgaard, Christine M., Creating the Kingdom of Ends (Cambridge: Cambridge University Press, 1996); and Reath, Andrews, Agency and Autonomy in Kant’s Moral Theory (Oxford: Clarendon Press, 2006).
12 For a discussion of the difficulties in developing constructivist norms that avoid ‘obscure and panicky metaphysics’, see O’Neill, Onora, ‘Constructivisms in Ethics’, cit. 7. As I hope to show, if the role of the principle of purposiveness for the project of the unity of reason is properly understood, there is no need to panic.
the results of his architectonic enterprise following his first Critique’s publication.
That there was some kind of reassessment of The Doctrine of Method is obvious if we reflect on the fate of Kant’s architectonic plans in the work that immediately followed the first edition of the first Critique: the Prolegomena to All Future Metaphysics that will be Able to come forward as Science. Here Kant seems very unkeen on constructive activities. ‘High towers and the metaphysicallygreat men who resemble them’, he simply writes in a footnote, ‘are not for me’ (Prol., AA IV: 373; 161).
One might think that this statement merely summarizes the position of the first half of the Critique of Pure Reason without adding anything to it. But that interpretation would be partial. As already emphasized, Kant’s cautious statements in the first part of the first Critique are complemented by the more ambitious ones that appear in the Doctrine of Method and onwards. Yet in the Prolegomena Kant seems to have abandoned those constructive ambitions. In the latter work we struggle to find hints to even a more modest type of activity that develops the findings of the Critique in the direction of the foundation of metaphysics as a science. Here, rather than the aspiration to demolish a certain kind of building in order to replace it with one that appears more adequate, in continuity with Wolff’s methodological prescriptions, the task of critical philosophy is to merely offer a survey of the foundation work. There is no hint of a ‘new plan’: the constructive enthusiasm of reason is restrained by an appeal to limit the project to its critical part.
To consolidate the sceptical interpretation, Kant’s caution towards all efforts directed at the foundation of metaphysics as a science is complemented by high praise for the work of David Hume, and an unmistakeable acknowledgement of its influence on his own thought.13 The Prolegomena is very clear on the priorities of a critique that needs to be complete in all its systematic parts, before metaphysics can even begin to become ‘a distant hope’ (Prol. 261; 58). This makes it difficult to avoid the objections of those who interpret the task of the critique as distinct from the mission of transforming metaphysics into science. If Kant had a passing interest in that transformation, sceptics argue, he rather quickly gave it up.14
13 Here, for example, we find the famous confession that ‘David Hume was the very thing that many years ago first interrupted my dogmatic slumber’ (Prol., 260; 57).
14 The evidence concerning Hume’s influence on the Prolegomena has shaped the views of generations of sceptically inclined readers of Kant’s first Critique. It was at the centre of a heated dispute among early Kant scholars between the end of the nineteenth and the beginning
How are we then to resist the force of sceptical interpretations of the critical task?15 One answer is to consider the successive development of Kant’s system, suggesting that the unity of reason remains an unfinished systematic project that occupies Kant until the Critique of Judgment, where the purposive principle of reflective judgment eventually enables a unified account of the relation between the theoretical and practical use of reason.16 The problem, on the one hand, is that apart from presenting a slightly stylized version of the three critiques (whereby The Critique of Pure Reason is about the conditions of possibility of theoretical knowledge, The Critique of Practical Reason is about the conditions of possibility of practical action, and The Critique of the Power of Judgment is about the relation between these two), the argument fails to do justice to the numerous references to
of the twentieth century (see amongst others Paulsen, Immanuel Kant, Sein Leben und seine Lehre (Stuttgart: Frommans, 1899); Erdmann, Benno, Kants Prolegomena herausgegeben und historisch erklärt (Leipzig: Leopold Voβ, 1878), LXXIX ff.; Fischer, Kuno, Geschichte der neueren Philosophie, vol IV, Immanuel Kant und seine Lehre (Heidelberg: Friedrich Bassermann, 1898), vol. 1, 217 ff. and 290 ff.; Vaihinger, Hans, Commentar zu Kants Kritik der reinen Vernuft, I (Stuttgart: Speman, 1881), 47 ff. and 340–348; and Riehl, Alois, Der philosophische Kritizismus, vol. 1 (Leipzig: Wilhelm Engelmahn, 1924), 308 ff. For a detailed reconstruction of the debate and its influence, see Gawlick, Günter, and Kreimendahl, Lothar, Hume in der Deutschen Aufklärung. Umrisse einer Rezeptionsgeschichte (StuttgartBad Cannstatt: Frommann Holzboog, 1987), 189 ff.
15 For a discussion of Hume’s influence on the Doctrine of Method and on later writings, see already Bauch, Bruno, ‘Parallelstellen bei Hume und Kant’, Kant-Studien, vol. 19 (1914), 521–524; and later Löwisch, DieterJürgen, ‘Kants Kritik der reinen Vernunft und Humes Dialogues concerning natural Religion’, Kant-Studien, vol. 56 (1965), 170–207. As far as the Prolegomena are concerned, an early commentator like Friedrich Paulsen already remarked that if it were not for the passages cited above, the influence of Hume on this work could be considered as marginal here as in the early Sixties. However, as Paulsen emphasizes, Kant’s debt to Hume in these passages is expressed in no ambiguous terms and ‘cannot be removed’, raising the question of whether there had been a return to Hume at the time of the Prolegomena. See Paulsen, Friedrich, Immanuel Kant, Sein Leben und seine Lehre (Stuttgart: Frommans, 1899), 98 and 101 ff. More recent scholarship has emphasized that despite the superficial evidence, the period of Hume’s clear influence on the thought of Kant should be dated at the beginning of the Sixties, as the Logik Blomberg also indicates. This is much earlier than the drafting of the Prolegomena and undermines interpretations that attribute to Kant a complete return to scepticism after the completion of the first Critique; more likely Kant was unsatisfied with certain aspects of it, including on questions of method, which are central to my interpretation. See on this issue the detailed study of Kreimendahl, Lothar, Kant. Der Durchbruch von 1769 (Köln: Dinter, 1990) 83 ff., and also chapter 2 (Zur Forschungslage), 15–82. See also for a thorough discussion the review in Brandt, Reinhard, ‘L. Kreimendahl, Kant. Der Durchbruch von 1769’, Kant Studien, vol. 83 (1992), 100–111.
16 See for readings to this effect, Allison, Henry ‘The Gulf Between Nature and Freedom and Nature’s Guarantee of Perpetual Peace’, in Proceedings of the Eighth International Kant Congress, edited by Hoke Robinson (Milwaukee, WI: Marquette University Press, 1995), 37–49, at 37–38; Guyer, Paul, ‘The Unity of Reason: Pure Reason as Practical Reason in Kant’s Early Conception of the Transcendental Dialectic’, The Monist, vol. 72 (1989), 139–167; and Nuzzo, Angelica, Kant and the Unity of Reason, cit. See also Freudiger, Jürg, ‘Kants Schlußstein: Wie die Teleologie die Einheit der Vernunft stiftet,’ Kant-Studien, vol. 87 (4) (1996), 423–435.
the unity of reason found in several earlier works.17 On the other hand, those few authors who resist this interpretation and suggest that Kant’s unified theory of reason is already present in earlier works, have been criticized for merely pointing out the functional analogies between theoretical and practical reason as parts of the same philosophical system but without really showing how an organic integration of these two uses has been achieved.18 But if we assume that Kant’s theory of the unity of reason was already complete by the time of the first Critique, why did he also refer to the unifying task as a project for the future rather than something that had already completed?19
To see the ambiguous status of the unity of reason in The Critique of Pure Reason, we need to turn to the description of metaphysics in its introductory pages. The fate of metaphysics is described here both in thoroughly negative and in surprisingly optimistic terms. On the one hand, the gloomy tone of Kant’s remarks about the inevitability of defeat whenever reason tries to make progress on metaphysical questions makes it hard to see how it might be possible to resurrect that defunct science, without falling into the errors of predecessors. On the other hand, the Critique of Pure Reason sets itself the task of transforming the ‘battlefield of these endless controversies’ (KrV, A VIII; 99) that is now called metaphysics into a secure path in which reason can advance without fearing either dogmatic despotism or anarchical scepticism. The need for metaphysics, Kant emphasizes also in the Prolegomena, is linked to the ‘interest of human reason in general’ for which it is necessary to admit that ‘a complete reform or rather rebirth of metaphysics, according to a plan completely unknown before now, is inevitably approaching’ (Prol, 257; 54).20
In analysing these remarks, several interpretations of the first Critique insist on the role of the practical interest of reason, and on how, as Kant explains, the apparent restriction to the speculative use of reason brings with it an important extension in its ‘absolutely necessary practical use’ (KrV, B XXV; 114). Without such a restriction, Kant emphasizes, practical
17 This has been pointed out in Kleingeld, Pauline, ‘Kant on the Unity of Theoretical and Practical Reason’, The Review of Metaphysics, vol. 52 (2) (1998), 311–339, who in turn argues that the unity of reason should be understood as a regulative ideal. See also Timmermann, Jens, ‘The Unity of Reason—Kantian Perspectives’, in Spheres of Reason, edited by Simon Robertson (Oxford: Oxford University Press, 2009), 183–198.
18 See for this critique Guyer, Paul, ‘The Unity of Reason: Rereading Kant.’ Review of Kant and the Unity of Reason by S. Neiman, The Philosophical Review, vol. 106 (2) (1997), 291–295.
19 Kleingeld, ‘Kant on the Unity of Theoretical and Practical Reason’, cit.
20 Emphasis mine (italics).
reason could not venture outside the boundaries of sensibility without encountering the obstacles of speculative reason and without falling into contradiction with itself (KrV, B XXV; 114–115). But what form does the justification of the legitimacy of the practical use of reason take in the first Critique? How does the claim about the unity of reason help clarify the relation between critique and metaphysics? What concepts enable the achievement of systematic unity? And where does Kant find the philosophical resources to make his account of the unity of the system immune to the objections encountered by his metaphysical predecessors?
Recent literature has insisted on the importance of the ‘unity of reason’ for Kant’s critical project, drawing attention to the systematic role of the ideas of reason. Many authors have argued that the purposive nature of ideas and the importance of realizing the highest good help us understand how Kant’s critical mission could be understood as both ‘negative’ and ‘positive’. On the one hand, the practical use of reason limits the wrongful extension of speculative to objects which are not given in sensible experience. On the other hand, it shows how understanding correctly the pure practical use of reason can ground belief in metaphysical concepts such as God, freedom, and the immortality of the soul.21
The aim of this book is to question this interpretation. My argument is that even though in the Critique of Pure Reason the unity of reason is achieved through the purposive function of the ideas of reason, the project ultimately fails to meet Kant’s own critical standards. It fails because, as I hope to show, in the first Critique practical reason has no distinctive domain for its own legislation, and no necessary connection to transcendental freedom: this is something that only begins to appear in the Groundwork, is developed further in the Critique of Practical Reason, and informs Kant’s analysis of purposiveness in the Critique of Judgment. It also fails because in the absence of that connection, Kant continues to relate the principle of purposiveness to the idea of intelligent design rather than to reason’s distinctive practical normativity. Kant’s return to the status of purposiveness, understood as normativity, in the context of the Critique of the Power of Judgment must be assessed in light of the problems that purposiveness as design faced in the first Critique.
21 For a review and critique of constructivist interpretations that is different from mine, see Kinnaman, Ted, ‘Problems in Kant’s Vindication of Pure Reason’, Journal of the History of Philosophy, vol. 39 (4) (2001), 559–580.
None of this should be surprising. When Kant was working on the Critique of Pure Reason, he did not anticipate writing a separate Critique of Practical Reason and another Critique of the Power of Judgment.22 On the contrary, as he announced in the famous letter to Markus Herz dating back to February 1772, ‘as far as my essential purpose is concerned, I have succeeded’ and ‘now I am in a position to bring out a critique of pure reason that will deal with the nature of theoretical as well as practical knowledge’ (Briefwechsel, 132; 135). As the introduction to the first edition of the Critique of Pure Reason also emphasizes, Kant clearly thought at that point that there was ‘not a single metaphysical problem’ that had remained unsolved (KrV, A XIII; 101). The part of the first Critique where this project is brought to completion is the Architectonic of Pure Reason. The Architectonic is the only section of the book where reason in its complexity is analysed from the point of view of the organic connection between its theoretical and practical use. The explicit aim of the section is to illustrate in what way the practical and theoretical use of ideas are not only functionally analogous, but integrated through a principle of purposive unity that helps in the transition from nature to freedom.
Analysing how the project of the unity of reason develops in the first Critique, exploring the demands that trigger it and understanding the constraints it encounters, help us shed light on the radically new direction the project takes in Kant’s later work. The pages of the Architectonic of Pure Reason are essential to see how the project of the unity of reason is executed in the first Critique but also to explain why Kant was later dissatisfied with it. This matters if we are interested in the evolution of Kant’s thoughts, but it is also key to clear some ambiguities on the relationship between purposiveness and the idea of God, that shaped subsequent critiques of
22 Not only does the first Critique lack any references to a new, forthcoming critique of practical reason but the Groundwork of the Metaphysics of Morals, published in 1785, explicitly rules out the need for one. As far as Kant was concerned, the task of clarifying the practical use of reason and the foundation of metaphysics as a science was all contained in the pages of the first Critique discussing the Canon of Pure Reason. For an instructive discussion of the genealogy of the Critique of Practical Reason, see Gonnelli, Filippo, Guida alla lettura della Critica della ragion pratica di Kant (Rome and Bari: Laterza, 1999), 3–24. As far as the Critique of Judgment is concerned, the work was only announced to Reinhold in 1787 under the title of a Critique of Taste. Here too the different title from the final edition and the division of the latter in Critique of the faculty of aesthetic judgment and Critique of the faculty of teleological judgment show that the problems Kant envisaged were rather different from the ones examined in the first Critique. See for a useful discussion of the genealogy of the work the editor’s introduction in Kant, Immanuel, Critique of the Power of Judgment (Cambridge: Cambridge University Press, 2000), xiii–xxii.
