Sed quid igitur sum? ‘But what then am I?’ The perplexing question posed by Descartes in the Second Meditation is one that has been agonized over by a host of philosophers in the Western tradition, before and since, but philosophical consensus on the answer is as far off today as it has ever been. There is a lot of dissatisfaction with some of the standard answers – the Cartesian answer that I am ‘in the strict sense’ an immaterial soul, the reductionist materialist view that I am a complex array of biological or neuronal mechanisms, and the eliminative view that there is nothing that I am, only a constantly shifting stream of consciousness – but no sign of agreement about the right way to proceed. Jonardon Ganeri, in this complex and erudite study, not only gives a remarkably clear overview of the main options in the modern Western philosophical landscape, but also aims, more ambitiously, to develop an alternative position, drawing on the ancient writings on consciousness and the mind offered by a variety of Indian thinkers from the first millennium.

The book opens with some insightful reflections on the naturalist outlook which so dominates contemporary anglophone philosophy. One of Ganeri's plausible thoughts here is that the commendable instincts that originally guided the naturalist programme – the aim of avoiding explanations that appeal to mysterious and undetectable agencies – have become progressively ‘usurped’, to the point where almost all our ordinary beliefs about ourselves that make up the ‘manifest image’ (in Sellars's phrase) have come to be regarded as somehow suspect. Going back to some of his Indian sources allows Ganeri to deploy a series of subtle distinctions between ‘hard’ naturalism of a type which (like modern scientific naturalism) focuses exclusively on ‘nature in the raw’, and more ‘liberal’ naturalisms, that ‘see nature richly attired in reason, norm and value’ (24).

Ganeri then develops his own account of human subjectivity, which involves a kind of interplay between three distinct dimensions in the concept of the self (all of which Ganeri later proceeds to explicate via quotations from the ancient Indian texts). First, there is an immersed self, characterized by a directly phenomenologically given sense of ‘mineness’, or ‘first person presentation in the content of consciousness’. Second, there is a participant self, which has to do with relations of involvement and endorsement: I do not merely passively ‘witness’ conscious occurrences, but actively ‘own’ them, through ‘clusters of commitments, resolutions and intentions’, all conditioned by ‘normative emotional responses’ (327). And finally there is an underself, a ‘procedural monitoring’, that involves ‘unconscious access to one's states of mind and their contents’ (14).

This last dimension might initially suggest that Ganeri has unearthed a proto-Freudian strand in first millennial Indian philosophy. But (if I understand it correctly) it has less to do with the kinds of tension and disruption studied by psychoanalytic theorists than with a whole workaday range of informational systems and functional routines whose processing operates below the threshold of consciousness. These include, for example, ‘retrieval of information from dispositional memory’ (262), and all sorts of other monitoring and feedback mechanisms without which what we call conscious sensation, let alone self-conscious awareness, would not be possible. The approach here (though Ganeri does not explore the parallel) seems consistent with the fascinating reflections (based on data coming in from modern brain and behavioural science) that have been offered by Ian McGilchrist in his remarkable The Master and his Emissary; these suggest that many previous models of the mind and the self have been too simplistic, and that we need to acknowledge that much of our mental life arises from a complex process of cooperation between analytic and highly conceptual modes of cognition on the one hand, and more ‘primitive’ modes of awareness on the other, many of the latter operating at a level that is largely opaque to the reflective analytic mind.

Ganeri's research into the Indian literature is impressive in its scope and detail, and he does his best to make it accessible. That is no easy task, given the difficulty in grasping the terminology for those unfamiliar with the exact connotations of the various original Sanskrit terms, which Ganeri conscientiously supplies in brackets in the course of the translated quotations. It is to be hoped that at least some readers will be encouraged to delve deeper into the vocabulary, for without the linguistic background, although the bare bones are there, the rich interlacing of covering sinews that gives shape to the whole is necessarily missing. But one suspects that few of the book's potential readers will be prepared to exert themselves to move beyond the complacently monoglot boundary within which so much contemporary anglophone philosophy seems content to operate.

Questions of language aside, there is considerable interest in seeing how the various philosophical moves associated with modern theories of the mind, involving notions like reduction, emergence, supervenience, and the like, were often anticipated in a tradition that is culturally and chronologically so separated from our own. And even those only able to get a schematic grasp of the ideas of the Indian philosophers will find much of interest in Ganeri's comparative evaluations of the debates going on in present-day philosophy of mind. The notoriously difficult problem of emergence receives particularly deft attention, with a concise and (it seems to me) effective demolition of the approach developed by the likes of John Searle, and still around in various forms today. The difficulty highlighted by Ganeri is that the notion of causal emergence (micro-neuronal features being causally sufficient for macro-mental features) is too weak to explain the autonomy of the emergent features (the fact that, as Searle puts it ‘once squirted out by the neurons they have a life of their own’); but if on the other hand we allow what Searle calls a ‘more adventurous’ notion of emergence (where the emergent features produce things that can't be explained by the causal behaviour of the neurons), this seems to erode the supposed dependence of the supervenient properties on the micro-structures from which they emerge (84).

The core of the puzzle about emergence hinges on the truth of the ancient maxim ex nihilo nihil fit. Nothing completely new can come into existence, or, as Ganeri puts it ‘nothing can come into existence which cannot be understood in terms of the nature of fundamental components and the ways they can be combined’ (82). This is the intuition that seems to be at work behind recent revivals of panpsychism (the arguments for which Ganeri again deftly demolishes). Ganeri's own resolution harks back to Cārvāka emergentism, which, he argues, can avoid the pitfalls of panpsychism on the one hand, and epiphenomenalism on the other. The key idea is the transformation of the base properties in the process of their combination: once transformed, the resulting properties can instantiate mental properties. And the difficulties besetting many forms of reductionism are neatly circumvented, because ‘it will be true to say that mental properties are reducible to the properties of the transformed physical base, but equally true that they are irreducible to the properties of the untransformed base’ (85).

There seems to be something right about this, but some doubts remain as to how much explanatory ground it really traverses. For what it seems to boil down to, in the end, is that when elements combine to form a complex system, the relevant micro-properties are changed so as to give rise to new causal powers in the resulting systems. Yet given the radical gulf between conscious mental properties and the micro properties of physics (the problem famously underlined by Descartes), we do not seem much closer to seeing how the latter, however transformed, could give rise to the former. Nevertheless, Ganeri's analysis at the very least succeeds in providing an illuminating conspectus of what is at issue in this baffling problem.

Emergence is but one of the many important issues tackled in a book whose scope extends over a large range of philosophical puzzles about the self. There are intriguing taxonomies of theories of the mind, ancient and modern, and an abundance of critical discussion, including an acute critique of the Buddhist view of the self. Both because of the clarity of its grasp of the contemporary landscape in analytic philosophy of mind, and because of the special slant given by the author's knowledge of Indian philosophy, the work has a lot to offer. While it would be unrealistic to expect from this (or perhaps any) book definitive solutions to the intractable problems of mind and body, Ganeri's understanding of what it means to approach these problems from a broadly naturalist perspective seems to me to be a good deal more nuanced, and more philosophically interesting, than much of the contemporary literature in the philosophy of mind.