In Kant's Elliptical Path, Karl Ameriks continues his project of understanding Kant's critical philosophy and its place in the history of philosophy that he also pursued in Kant and the Fate of Autonomy: Problems in the Appropriation of the Critical Philosophy (CUP, 2000), Interpreting Kant's Critiques (OUP, 2003) and Kant and the Historical Turn: Philosophy as Critical Interpretation (OUP, 2006). The method and structure of Kant's Elliptical Path will be familiar to those who have read these. Here again Ameriks collects essays written for other occasions, but also argues that these essays together make the case for a particular reading of Kant and his place in the history of philosophy.

Kant's Elliptical Path builds most directly on Interpreting Kant's Critiques. There Ameriks argued that Kant's Critical philosophy must be understood in light of its distinctive aim and method, and not just in terms of its well-known doctrines (transcendental idealism, the categorical imperative, ethico-dogmatic theology and so on). The aim of the Critical philosophy is the modest one of making sense of and validating common sense experiences – for example, that there is an external world, that morality presents us with binding commands, and that there are valid judgements of taste. Corresponding to this aim, Kant's philosophical method is regressive: it begins with common sense experiences and then moves to the principles and commitments necessary to sustain them. The distinctively Kantian twist is that common sense experience implies transcendental idealism, the discipline of reason, and that autonomy is the supreme principle and end of humanity.

In Kant's Elliptical Path Ameriks expands on these interpretations of the aim and method of Kant's philosophy. So, while Ameriks once again defends an impressive number of claims about the doctrines of Kant's philosophy and its historical significance, once again these claims are meant to support general theses about the aim and method of the Critical philosophy.

Ameriks's first main thesis, then, is about the development and aim of the Critical philosophy. Ameriks now argues that Kant's Critical philosophy was defined by his encounter with Rousseau in the early 1760s and that the aim of the Critical philosophy is to explore and sustain ‘Rousseau's vision of what is most central in our human nature’ (p. 45), namely, ‘moral freedom’ (p. 39) or ‘autonomous freedom’ (p. 3), so that autonomy is both the source of human dignity and the fundamental end of humanity (pp. 2–3, 5, 39). This thesis explains the title of the book: Kant's elliptical path goes from his 1760s turn to Rousseau's view of humanity and human dignity, continues through the Critical philosophy and transcendental idealism necessary to defend this view of humanity and human dignity, and then returns to validate common sense and the affirmation of autonomy as the fundamental end of both individuals and human history.

Ameriks's second main thesis is about Kant's philosophical method: Ameriks now argues that Kant's philosophical method is elliptical, meaning that Kant generally works from common sense experience to transcendental idealism and then back to the vindication of common sense experience.

So, where Ameriks in Interpreting Kant's Critique argued that Kant's aim is to sustain common sense and that Kant's method is regressive, he adds in Kant's Elliptical Path that the defining aim of Kant's philosophy is to sustain the commitment to autonomy that resulted from Kant's encounter with Rousseau, and that Kant's method not only regresses from common sense to its presuppositions, but also returns from presuppositions to explain and vindicate common sense.

On Ameriks's reading, the elliptical shape is ubiquitous in Kant's philosophy. First, there is the elliptical path that Ameriks argues Kant's thought took from the early 1760s to the late 1790s. Second, there is the elliptical method that Ameriks argues is Kant's philosophical method. Because of this aim and this method, Ameriks also identifies numerous elliptical arguments in Kant's philosophy (more on these below). Moreover, Ameriks suggests that Kant conceives of human history as an ellipse that begins with original innocence, then goes through the period of science, enlightenment, and culture and vice, before it culminates in the wise innocence that is the realization of humanity's fundamental end.

A reviewer of Kant's Elliptical Path has a choice to make. The review can focus on one or some of the claims about the doctrines of the Critical philosophy and their place in history – Ameriks's particular interpretations of transcendental idealism, the fact of reason, Kant's philosophy of history, and so on. Or the review can focus on the general theses about the development, aim and method of the Critical philosophy. (It would be foolhardy to try to do both.) I pursue the second option. So, in the following I neglect Ameriks's many interesting interpretations of the elements of Kant's Critical philosophy in order to discuss whether Ameriks succeeds in establishing his general theses about the aim and method of the Critical philosophy.

First, then, the thesis that the aim of the Critical philosophy is to sustain Rousseau's vision that autonomy is the source of human dignity and the vocation of both individual human beings and humanity. According to Ameriks, Kant saw that Rousseau's vision needed a philosophical defence and that especially the scientific revolution presented a challenge to the libertarian sort of human freedom that the Rousseauian vision presupposes (chapter 1). On this reading, Kant's ethical theory did not abruptly change from a pre-Critical empiricist and sentimentalist ethics into a Critical rationalist and purist ethics. Rather, Kant's basic ethical theory, the aim of vindicating the authority of morality, and his commitments to autonomy, rationalism and purism were set already in the 1760s, though developments in Kant's theoretical philosophy provided the materials he needed to clear the theoretical space and prepare the ground for the theory, realize the aim and sustain the commitments (chapter 2).

Part II of the book (chapters 3–12) is meant to illustrate how the three Critiques can be understood as presenting the Critical defence of Rousseau's vision: chapters 3–5 deal with issues related to the first Critique, chapters 6–9 with the second Critique and chapters 9–12 with the third Critique.

In chapters 3 and 4 Ameriks defends a moderate reading of transcendental idealism as implying ‘a coherent, expansive, and multilevel realist metaphysics’ (111) and contrasts this reading with the interpretations of Wood, Hanna, Langton and others. In chapter 5 Ameriks uses Schleiermacher's analysis of Kant's treatment of the self as tool for contrasting Spinoza's and Kant's theories of the self.

Chapter 6 discusses how we should understand the Kantian notion that human beings are in the world, while the world is in or for human beings. In Chapter 7 Ameriks defends his interpretation of the fact of reason argument from criticisms raised by Kleingeld and Sussman. Chapter 8 contrasts Kant's and Reinhold's theories of the relation between freedom, reason and the will.

Chapter 9 presents a reading of Kant's essay ‘Idea for a Universal History with a Cosmopolitan Aim’. Chapter 10 argues that Kant's reviews of Herder's Ideas for the Philosophy of the History of Humanity reveal a deep disagreement about what philosophy and philosophical method should be, but also that this disagreement set the stage for Reinhold, Hegel, Schelling and later philosophers to wed the poetic and scientific orientations of philosophy. Chapter 11 presents a reading of sections 90 and 91 of the third Critique and discusses the modality of Fürwahrhalten appropriate to freedom, God and immortality when these are cognized on practical grounds alone. Chapter 12 discusses Kant's ‘anti-supernatural Enlightenment ideas’ (p. 260) as evidenced by his critique of belief in miracles and how these ideas are consistent with his claim that we can (and ought to) believe in freedom, immortality, God and providence.

In the remaining chapters of the book Ameriks discusses appropriations and extensions of Kant's elliptical path in Hölderlin and Novalis (chapter 13), why tragedy became a central notion in German philosophy after Kant (chapter 14), and why and how we should do history of philosophy (chapter 15).

Now, Ameriks's first thesis consists of two claims: first, that Kant's encounter with Rousseau defined the aim of the Critical philosophy, so that ‘once Kant had been “turned around” by closely reading Rousseau … his most fundamental views did not radically change’ (p. 1). Accordingly, the Critical philosophy ‘simply provided Kant with an ideal means … to fill out a systematic defence that allowed for a return to his deepest pre-systematic beliefs’ (p. 1). The second claim is that the definitive aim of Kant's philosophy is to do justice to ‘the ultimately unconditional and non-spatiotemporal value of the dignity of persons as beings with a capacity for free agency oriented toward a pure respect for reason’ (p. 3). In short, Kant's encounter with Rousseau defined the aim of the Critical philosophy and the aim is to sustain autonomy as the principle of humanity and the source of human dignity. I doubt both claims.

First, Ameriks shows that we have good reason to believe that Kant's encounter with Rousseau was important for the development of the Critical philosophy, and Ameriks also shows that we can read the critical philosophy as aiming to ground and sustain Rousseau's vision. Yet, ‘can’ does not imply ‘ought to’. Ameriks is in good company in asserting that there is a definitive influence on Kant; candidates for this lead role include Descartes, Wolff, Hume, Garve, Rousseau and, lately, Milton. But I doubt that any one of these should be singled out as the definitive influence. Indeed, we might take this plurality of candidates for the lead role to indicate that we ought to abandon the search for a leader. Ameriks's choice of Rousseau for the part follows a recent tendency to emphasize the influence of Rousseau – a tendency reinforced by the new edition and translation of Kant's Remarks. This tendency is welcome insofar as Rousseau's influence on Kant had been somewhat neglected (the work of Cassirer, Velkley, Wood and others notwithstanding). But there is a difference between claiming that Rousseau was an important influence on Kant and claiming that he was the most important or definitive influence. While Ameriks's argument establishes the former claim, it does not establish the latter.

I have similar worries about the second part of the first thesis: the claim that the Critical philosophy has the sustenance of autonomy as its defining aim. My problem here is not that I doubt that sustaining autonomy is important for Kant – clearly it is. My problem is that I find it hard to believe that there is a single supreme aim of the Critical philosophy that gives sense to all of its parts. Once again Ameriks is in good company in asserting that there is such a supreme aim, and once again there is a plurality of candidates, including the aims of defeating scepticism, finding a path between rationalism and empiricism, vindicating the authority of morality, validating the objectivity of science, affirming the rationality of religion, making sense of human freedom and establishing the unity of reason. But once again I am doubtful that any one of these is the supreme aim of the Critical philosophy. Indeed, just as with the plurality of influences on Kant, I find the plurality of readings that assert a single supreme aim indicative of the poverty of each of them. The fact that the Critical philosophy has these aims without any clear indication from Kant that one of them subordinates the rest invites the conclusion that the Critical philosophy has several coordinate aims. And, again, while Ameriks shows that the sustenance of autonomy is an important aim of the Critical philosophy, he does not show that it is the supreme aim.

Ameriks might reply that he only meant to defend the weaker claims that Kant's encounter with Rousseau was important and that one important aim of the Critical philosophy is to sustain autonomy. Yet, this reply makes the first thesis trivial; few (if any) would disagree with these claims. Moreover, the title as well as the text strongly suggest that Ameriks's claim is that Kant's encounter with Rousseau defined the elliptical path of Kant's philosophy and that we can understand this path in terms of autonomy.

My problem with the first thesis is partly structural: Ameriks's argumentative strategy is to collect a series of essays on various topics and then suggest that these together support a general conclusion about the aim of the Critical philosophy. The problem is that the essays in Kant's Elliptical Path only rarely relate to this general thesis and so offer slim support for it.

I do, on the other hand, think that Ameriks succeeds quite well in defending his second main thesis: that Kant favours the elliptical philosophical method. Here the structure and content of the book work much better to support the thesis: every essay offers a new opportunity to exemplify the elliptical method at work and every essay thus adds support to the thesis that this is indeed Kant's favoured method.

Ameriks shows how Kant's treatment of our relation to the external world (chapters 3, 4 and 6), religion (chapters 11 and 12), the nature and authority of morality (chapters 7, 8, 11 and 12), moral motivation and the feeling of respect (chapter 2), history (chapters 1, 11 and 13) and many other topics follow the elliptical method. And in each of these cases Ameriks shows how we can better understand what Kant is doing and how he is doing it, once we read his arguments in light of this method. I thus think that Ameriks quite persuasively defends the thesis that Kant generally employs the elliptical method and shows the fruitfulness of reading Kant with this method in mind.

Of course, this conclusion about method also offers insight into the aim of the Critical philosophy – if not as dramatic an insight as the one Ameriks was aiming for. That Kant uses the elliptical method shows that one aim of the Critical philosophy is to make sense of and vindicate common sense experiences, whether of the theoretical, practical or aesthetic sort. Even if Ameriks defended this conclusion already in Interpreting Kant's Critiques, and even if it is less dramatic than the thesis that the aim of the Critical philosophy is to sustain a Rousseauian turn to autonomy, it remains an interesting conclusion.

Moreover, even if we have reason to doubt that Kant's thought developed along the elliptical path that Ameriks suggests, Kant's Elliptical Path is a treasure trove of original and masterfully supported interpretations of Kant's philosophy. But more than that, Ameriks weaves together the interpretative project of making sense of Kant's writings and the various doctrines, aims and methods of the Critical philosophy with the historical project of understanding the influences on Kant, the development of Kant's philosophy, the reception of the Critical philosophy by Kant's contemporaries and the wider impact of the Critical philosophy on German idealism, romanticism and beyond, and the evaluative project of assessing Kant's arguments, his philosophical doctrines, aims and method, and the constructive project of articulating what the interpretative, historical and evaluative projects teach us about what philosophy is and how it should be done.

Given this level of ambition it is only fair that Kant's Elliptical Path is demanding. Most of the essays presuppose knowledge of Kant's writings and Kant scholarship. Moreover, many of the essays serve multiple argumentative roles that the reader must navigate to get the full benefit: they defend a particular interpretation of some part of the Critical philosophy and its historical influence, and they support the general theses of the book, and at the same time also serve as parts of an ongoing elaboration and defence of Ameriks's interpretative positions that he developed in earlier writings. So, quite a few of these essays not only presuppose knowledge of Kant's writings and Kant scholarship, but also require some familiarity with Ameriks's earlier work and the criticisms it has met. Of course, demandingness is not a vice. Those equipped to follow Ameriks's intricate (if not elliptical) lines of thought will be handsomely enriched by Kant's Elliptical Path.Footnote ¹