Gilles Marmasse's book is both a voluminous and an ambitious work. Throughout its 460-plus pages, Marmasse offers a detailed analysis of two of the three parts of Hegel's system of philosophy, namely the philosophy of nature and the philosophy of spirit, or what Hegel calls the ‘real sciences’ (die realen Wissenschaften). Marmasse's central hypothesis is that Hegel understands nature and spirit as opposed but nevertheless closely interconnected entities, and that the latter strives to ‘solve the aporias implied by the former’ (10). In Marmasse's own words, Hegel's notion of spirit is to be conceived as ‘nothing but the subject who both theoretically and practically engages with nature considered as a manifold and contradictory given’ (10).

Although Marmasse often refers to the Phenomenology of Spirit, and to a lesser extent to Hegel's earlier philosophical writings, his concern is essentially with Hegel's latest systematic works, namely Science of Logic, Elements of Philosophy of Right, the Heidelberg and Berlin Lectures and, of course, the different versions of the Encyclopedia of the Philosophical Sciences. Yet Marmasse does not examine the content and issues inherent in Hegel's argument as they systematically unfold in the second and third section of the Encyclopedia. Instead, he chooses to focus on particular themes, which in one way or the other are aspects of Hegel's understanding of the relationship between nature and spirit. This approach allows him to shed light on some key notions by which Hegel conceptualizes this relationship, such as ‘negation’ and ‘sublation’, and furthermore to revisit a certain number of controversial issues, which in many ways continue to be at the centre of the debates surrounding Hegel's philosophy as a whole.

It is by briefly outlining two such controversial issues that I wish to illustrate the position defended by Marmasse throughout his book. First of all, in chapter 6, Marmasse challenges the common view of the notorious habilitation thesis on the orbit of the planets that Hegel wrote in 1801 as he was attempting to secure a position at the University of Jena. Hegel is generally thought to have erroneously condemned the discovery by Johann Tietz in 1766, and published by Johann Bode in 1772, of the mathematical equation that allowed the calculation of the distance between the planets of the solar system. Hegel is furthermore accused of having simply ignored Giuseppe Piazzi's important discovery of the planet Ceres while he was writing his habilitation thesis. However, as Marmasse's detailed analysis demonstrates, such accusations prove to be unfounded. Hegel, Marmasse argues, did not ignore Piazzi's discovery. Instead, he was being cautious about what, at the time, was still an unconfirmed hypothesis. As for Tietz's and Bode's mathematical conjecture, Hegel, in line with Newtonian physics, was resolutely sceptical about the possibility that, in the fields of physics and astronomy, mathematics and geometry could successfully replace experience and observation.

What is significant here, beyond the sole episode of the Dissertationschrift, is the common reproach that Hegel simply omits, and even goes against, factual truths of the natural sciences and common empirical experience. According to many authors, Hegel's philosophy is a more or less extravagant intellectual enterprise which forces empirical reality into the procrustean bed of pure, a priori thought. For Marmasse, this reproach is based on a misunderstanding of Hegel's conception of the relationship between philosophy and the empirical sciences. Hegel, Marmasse argues, insists that empirical reality, experience in general, or whatever is given as ‘external world’ or ‘nature’ is nothing but the starting point or the presupposition of philosophy. For Hegel, philosophical investigation begins with what first presents itself as an ‘immediate’, ‘irrational’, empirical and factual given. Hegel does not conceive of philosophy as a discipline competing with the empirical sciences, nor does he consider its task to consist in the elucidation of the foundations of such sciences. Rather, Marmasse argues, Hegel's view is that philosophy differs from empirical sciences in that it does not ‘extrapolate’ or ‘generalize’ on the basis of the multifarious aspects of empirical reality. Instead, philosophy is concerned with what Hegel calls the ‘concept’ of such reality, with its internal logic or principle. For Marmasse, this conception of philosophy is best described as a process of idealization, which is essentially a process by which reason, for its own sake, establishes and generates the immanent unifying principle governing the manifold of empirical reality. As Marmasse writes:

It is in this sense that philosophy, unlike the empirical sciences, is autonomous and legislative rather than dependent upon reality.

The second controversial issue concerns Hegel's system of philosophy as such. In Chapters 3, 5 and 12 Marmasse challenges the common objection that Hegel's system purports to conceptualize the ‘complex’, ‘manifold’ and more or less ‘unpredictable’ life of a given object, a given ‘figure’ or a given ‘moment’ of spirit, but actually obeys a deterministic, necessary and/or teleological logic. According to Marmasse, such a criticism fails to take into account the logic that rules the transition from one section, or one moment, of Hegel's system to another. As Marmasse indicates, the key notions to understand the developmental process of Hegel's system are ‘negation’ and ‘sublation’. Each moment of the system can be said to develop by means of a process of negation and sublation: every analysis begins with an immediately given which is then negated, and in turn, negated and sublated into a ‘higher’ unifying principle. This procedure entails, Marmasse argues, that each moment relates to all other moments—or, to use Hegel's vocabulary, is meditated by the other—but without being positively conditioned by it. In other words, the relationship between the moments within the system is by no means to be understood in positive terms, as the deterministic and especially the teleological models suggest.

Although Hegel often describes the systematic process in terms of development (Entwicklung), progression (Fortgang) or actualization (Verwicklichung), such vocabulary is not intended to describe a process by which, for example, a possibility contained within a specific moment is simply being actualized in the following one. Instead, what is being actualized is the result of a negation and sublation of what in the preceding stage came to be perceived as inadequate, insufficient or one-sided. As Marmasse puts it: ‘insofar as the moments mutually negate each other, the Aristotelian scheme according to which a form realizes itself within matter is inadequate to describe the becoming of an Hegelian cycle’ (131). Marmasse clarifies this by using an example drawn from Hegel's philosophy of history, according to which the modern world is not the result of an inherent possibility allegedly contained in what Hegel calls the oriental world. Admittedly, Hegel considers the notion of freedom to have been present already in the oriental world. Yet, in the course of history leading from the oriental to the modern world, the initial determination of freedom necessarily comes to be considered as inadequate to its own concept and is therefore being negated and sublated time and again. For Marmasse, negation and sublation are to be understood as referring not to a simple process of actualization, but rather to a transformation that deeply changes both form and content. As a result, the modern notion of freedom cannot in any way be considered as being simply the actualization of what was formally and potentially present within the oriental world.

This being said, Marmasse does not limit himself to an analysis and defence of Hegel's philosophy, but also explores the ambiguities and difficulties in the development of Hegel's argument. By doing so he identifies a certain number of themes and issues, which, in his view, have lost their relevance for us. As he straightforwardly states in his concluding remarks: ‘in a certain way, Hegelianism belongs to the past by its themes of investigation, its presuppositions and method. Today, Hegelianism essentially is not an object of debate but of history’ (405).

Does Marmasse's book live up to its ambitions? In many ways it does so with great success. Indeed, throughout its fourteen chapters Penser le réel provides numerous extremely valuable insights into Hegel's philosophy of nature and spirit as well as many insights into his logic. Moreover, Marmasse convincingly responds to both the recurrent criticism mentioned above and other pervasive criticisms of Hegel's systematic philosophy. In particular, Marmasse, in my view, accurately challenges Karl Löwith's view that Hegel's philosophy of history is nothing but a philosophical transposition of the Christian, eschatological, conception of ‘the end of history’. According to Marmasse, this reading disregards the fact that, for Hegel, history is not divine, but unfolds, so to speak, within the element of human finitude and mortality. Therefore, Hegel's famous thesis on the ‘end of history’ is not to be understood as a flight out of history, but rather as an immanent process that is affected by finitude and realizes itself only partially. Furthermore, Marmasse also accurately defends Hegel against Heidegger's claim that Hegel's philosophy is the accomplishment of metaphysics understood as onto-theology. In Marmasse's view, the ultimate element in the Encyclopedia is not a being, but rather ‘an activity of idealization of being’ (79). Nevertheless, Marmasse's thematic approach entails that his examination of the various texts that Hegel devoted to these subjects is rather fragmented and lacks the in-depth analysis that each of them would require. More often than not, Marmasse refers to different aspects of Hegel's philosophies of nature and spirit not for their own sake, but in order to illustrate how Hegel conceives of the relationship between logic, nature and spirit. Evidently, dealing with so many complex issues within a single work is a very challenging task. As I see it, Marmasse's book would have benefited from reducing the number of issues discussed in relation to both Hegel's philosophy of nature and spirit.

First and foremost intended for students and scholars working in the fields of Hegel studies, German idealism and post-Kantian philosophy, Marmasse's work will surely be appealing to anyone interested either in specific aspects of Hegel's philosophy of nature or of spirit or in Hegel's philosophy as whole. Although dealing with extremely complex issues, Marmasse's style is simple and precise, and his explanations are instructive and illuminating. Moreover, he develops a nuanced position that is likely to convince many readers. For these reasons, this book offers a significant contribution to the study of Hegel's mature system of philosophy.