What does it mean to say ‘I’? Starting from this question, Paolo Diego Bubbio’s book aims to develop an account of the ‘I’ that moves beyond what he describes as the traditional dichotomy between subject and object. To this end, he engages with the work of Hegel and Heidegger, arguing that both thinkers share a ‘non-subjectivist’ understanding of the ‘I’. Subjectivism is one horn of the dilemma that the book seeks to overcome, with the other being objectivism—understood as the naturalistic approach that Bubbio sees as prevalent in contemporary philosophy of mind.

What, then, does Bubbio mean by the subjectivist conception of the ‘I’? Bubbio contrasts a third-person account of the subject, which he identifies with the objectivist conception, with a first-person account. However, the subjectivism under attack in Bubbio’s enterprise cannot consist in a first-person account of what it means to say ‘I’: for this would imply that a ‘non-subjectivist’ account of the ‘I’ ignores what he himself calls the irreducibility of the first-person point of view.

The first chapter clarifies that subjectivism refers to the notion of the ‘I’ as a substance. This notion is foreshadowed in the introduction, where Bubbio states that a central aim of his book is to challenge the ‘thinghood’ often associated with the terms ‘I’ and ‘self’. The roots of subjectivism are traced to the Cartesian idea of a ‘self-sufficient underlying subject’—the res cogitans—a view that Bubbio appears to extend to Kant and Fichte. This attribution is somewhat surprising, as it risks conflating two distinct issues: the critique of subjectivism as a conception of the subject in terms of a substance and the problem of subjective idealism, as attributed here and elsewhere to Kant. Kant’s account of the ‘I’ in the Critique of Pure Reason is explicitly anti-substantialist; the ‘I’ of the ‘I think’ is not a representation of an entity but the formal condition of any representation. Kant criticizes both empirical and rational psychology for reifying the ‘I’. In this light, subjectivism understood as the conception of the subject as a substance cannot be assimilated to the first-person account, which, in Kantian terms, is precisely opposed to the reification inherent in empirical and rational psychology.

By not engaging explicitly with Kant’s treatment of the ‘I’, the book misses an opportunity to situate its critique of ‘subjectivism’ more firmly within the critical tradition that Hegel and Heidegger themselves inherit and transform. Both Hegel’s account of Geist and Heidegger’s analysis of Dasein emerge as responses to Kant’s insights, while both seek to overcome subjective idealism. Addressing this Kantian background would have sharpened the different contributions of Hegel and Heidegger and clarified subjectivism as an account of the ‘I’ in terms of a thing, as opposed to a first-person account of the ‘I’, and the question of subjective idealism. It would also have clarified whether the object of his analysis is the ‘I’ of the ‘I think’ or the empirical ‘I’. If the latter is in question, this would explain why Bubbio places the issue of identity formation at the centre of his enterprise, linking it to lived experiences, cultural practices and shared histories. This connection is undeniable, but it seems to broaden the scope of the inquiry. How do these considerations relate to the specific question of what it means to say ‘I’? Should we not distinguish between the question of the nature of self-reference, or the ‘I’ as a formal condition of thought, and the identity of a particular subject as it develops in social and historical contexts? If not, what justifies treating these questions as unified, when there is a danger of conflating different problems?

As I understand his approach, Bubbio is concerned with the very concept one has of oneself as a subject in using ‘I’. What do we know, or what should we say, about what it means to be a subject, to be able to use ‘I’? Bubbio’s central aim in the book then is to account for this concept of oneself as a subject in the light of what he sees as its two necessary conditions: nature and history. Against the notion of the ‘I’ as a self-standing thing, Bubbio argues that we must understand the ‘I’ (and I take this to mean the concept one has of oneself) as relationally constituted: through one’s engagement with nature, through the inheritance of a history, and through acts of mutual recognition—this idea recurs throughout the text as its primary thesis.

The book is structured into three main parts, each comprising three chapters. Part I focuses on Hegel and examines (1) the relationship between the concept of ‘I’ and the concept of Geist, (2) the relationship between the ‘I’ and nature, and (3) the role of history in the identity of the ‘I’. Part II turns to Heidegger, exploring (1) the meaning of Dasein in Being and Time and Heidegger’s reading of Hegel’s concept of experience, (2) the engagement of Dasein with nature, and (3) the normative implications of the notion of authenticity. Part III synthesizes insights from both thinkers to develop a relational and perspectival model of ‘I-hood’. This section includes (1) discussions of underexplored pathways in their philosophies, (2) the interplay of myth and experience in shaping the self, and (3) a concluding chapter outlining the resulting framework for understanding the ‘I’ as fundamentally relational and perspectival, moving beyond subject-object dualism.

In Bubbio’s reading of Hegel, the ‘I’ emerges through a historical process that begins in nature and culminates in mutual recognition. This interpretation places Bubbio alongside scholars such as Robert Pippin, who draw on Hegel to sketch an outline of human agency constituted through social practices of recognition—though Bubbio also emphasizes the role of nature in this process. Central to Bubbio’s interpretation of Heidegger is his critique of Cartesian and Husserlian models of the self, which are here presented as abstractions that isolate the concept of the self from its lived, historical context. For Bubbio, Heidegger’s analysis of Dasein reveals how the self is constituted through its engagement with the world.

However, in both cases, the language of the ‘emergence’ of the ‘I’ invites scrutiny. If, as Bubbio claims, the Hegelian ‘I’ is constituted through mutual recognition, then it is unclear in what sense it can be said to emerge or be transformed through a process, given that there would be no ‘I’ prior to that recognition. Likewise, if Dasein is always already being-in-the-world, how can it be said to ‘emerge’ through its engagement with the world? If this notion is meant to counter a substantialist conception of the subject as fixed and self-sufficient, it runs the risk of framing the alternative in terms that are tributary to the categorical framework one seeks to overcome.

Paolo Diego Bubbio’s Hegel, Heidegger, and the Quest for the ‘I’ is an erudite and ambitious work. Its approach unfolds through sustained engagement with the texts of Hegel and Heidegger, drawing on a wealth of references and tracing the development of their work. At times, the presentation could benefit from greater clarity and a more systematic structure. While rich in systematic claims, the book sometimes moves too quickly between key concepts and themes, and some transitions might have benefited from a more sustained engagement with the material. Certain claims, too, might have been strengthened by further development. A more deliberate development of arguments would have improved the accessibility of this otherwise thought-provoking contribution.