As the reach of its title indicates, and to echo the seriousness with which Socrates initiates the discussion in Plato's Republic, the problem addressed in Thinking Like a Planet ‘is no chance matter but concerns how we should live our lives’ in face of the greatest environmental challenges that humanity has encountered. In the author's view, these comprise primarily the onset of unprecedented global climate change, ozone depletion and the mass extinction of species. Callicott's volume thus stands alongside recent work by Stephen GardinerFootnote ¹ and Dale JamiesonFootnote ² (both of whom receive critical yet respectful attention) in aiming to forge the conceptual and normative resources that might prove equal to the challenge. Nor is it an accident that the title echoes a title of one of Aldo Leopold's entries to his Sand County Almanac – ‘Thinking Like a Mountain’Footnote ³. For it is to Leopold, once again, that Callicott turns for his inspiration.

Baird Callicott's work ‘has long been associated with the Leopold legacy’ (13). Thinking Like a Planet deepens and extends this association. It does this, first, by revising and accommodating Leopold's land ethic to the developments in evolutionary biology and ecology that have occurred since Leopold wrote his Sand County Almanac (Part One); and second, by building a new ‘Earth ethic’ out of some thoughts that Leopold first penned in 1923 in his essay on ‘Some Fundamentals of Conservation in the Southwest’, which is helpfully reprinted as an appendix to the current volume (Part Two). Callicott is insistent that the Earth ethic ‘complements and supplements the land ethic; it does not succeed or replace it’ (12). Together, they form ‘a new comprehensive environmental philosophy for the twenty-first century’ (13).

The land ethic deals with issues that can be addressed within standard ecological spatial and temporal parameters, and many of its features, as these have been articulated and elaborated in Callicott's earlier writings, remain in place. Callicott's Leopold is a ‘worldview remediator’ (32), who builds on foundations laid by Hume's theory of the moral sentiments, the existence of which is in turn to be explained by Darwin's theory of natural selection. The land ethic enlarges Charles Elton's concept of the ‘biotic community’ to include ‘soils, waters, plants and animals’ to deliver the central recommendation that we should look upon land as ‘a community to which we belong’, rather than as ‘a commodity belonging to us’. The proposal thus entails the transformation, indeed the reversal, of our relationship to the land as this is traditionally conceived. The fact that it embodies a ‘holistic’ rather than individualistic moral ontology (44, 292–295) is attributed by Callicott to its Humean ‘agent-based’ foundations. It is based on the capacities of moral subjects rather than the capacities of moral objects, and ‘just as our moral sentiments are many, so are their proper objects’ (60). This point is crucial, since it lets in concern for ‘wholes’, such as societies, communities and even ecosystems.

But Leopold's land ethic is framed by the ecology of his time, shaped by the likes of Frederick Clements, Eugene Odum, Arthur Tansley and Charles Elton. The revision of the land ethic undertaken in Part One is necessitated chiefly by the rise of a more ‘stochastic’ understanding of ecological processes which regards disturbance rather than stability as the norm. Leopold's original normative prescription had read: ‘A thing is right when it tends to preserve the stability, beauty and integrity of the biotic community; it is wrong when it tends otherwise’ (96). Callicott proposes a suitably adapted version: ‘A thing is right when it tends to preserve the beauty of the biotic community and to disturb it only at normal spatial and temporal scales. It is wrong when it tends otherwise’ (97).

The need for an Earth ethic, the subject of Part Two, arises from the fact that ‘the land ethic is … a poor fit with the most urgent and dire environmental concern of our time. To have some chance of confronting global climate change successfully, we need to be equipped with an environmental ethic that is commensurate with its spatio-temporal scale’ (300). Callicott begins his search for such an ethic by once again taking his cue from Leopold. In the third section of ‘Some Fundamentals’, entitled ‘Conservation as a Moral Issue’, he finds ‘three … foundations on which to build an Earth ethic’ (157) The first is a ‘three-pronged’ virtue ethic, comprising personal, craft and social dimensions. The second is responsibility both to ‘immediate posterity’ and to ‘the unknown future’. The third is respect for the earth as a living, or even conscious, being. Each was suggested to Leopold himself by his reading of a passage from Ezekiel.

Callicott valiantly pursues the third of these ideas through the best part of two chapters, taking in the metaphysics of Pyotr Ouspensky and that of his fellow-Russian Vladimir Vernadsky, before finally settling on James Lovelock's Gaia hypothesis as the best exemplar of the idea. Though reluctant to abandon the notion that the Earth is, in some sense, a living being, he falters over the attribution of consciousness, commenting that ‘for purposes … of grounding a non-anthropocentric Leopold Earth ethic, whether the Earth has or has not a soul or consciousness matters little’ (206). (This is slightly disconcerting for the reader who has struggled thus far to keep up.)

From a biocentric perspective, a living being does not need to be conscious to command respect and be granted moral standing, but from the various biocentric theories on offer, Callicott favours that advanced by Kenneth Goodpaster on the grounds that it does not require a ‘conative’ understanding of life – where conation might include anything from a desire to a mere ‘direction of growth’ (231), none of which may reliably be attributed to the Earth. In the end, however, Callicott will reject a non-anthropocentric Earth ethic on the grounds that it involves ‘a leap beyond … the spatial and temporal limits of ethics’ (301) – presumably because caring for all life, forever, is beyond us. Instead, he proposes an anthropocentric Earth ethic that (i) addresses global climate change insofar as it affects global human civilisation; (ii) is within our motivational repertoire to care about; and (iii) can at the same time be treated as surrogate for a concern for ‘the unknown future’. Crucial to this proposal is the thought that ‘what does appear to be threatened by global climate change is the Holocene climate and the biota that is adapted to it’ (298); by this he means human civilisation and the biota with whom we are ‘fellow-voyagers … in the odyssey of evolution’ (29).

Essentially, then, Callicott's Earth ethic retains the same foundations as his land ethic but shifts the focus from the land community to global human civilisation and, more generally, the biota adapted to the Holocene climate. It is a focus judged to extend but not overwhelm ‘our capacity for a genuine and effective moral response’ (301).

Since analytic philosophers are playfully likened to hungry barracudas (223), even a retired barracuda might be permitted to pick a bone or two. To begin with, the handling of the concept of ‘anthropocentrism’ is, in two respects, puzzling. On the one hand, even though moral anthropocentrism is initially characterised as limiting ethical regard to human beings (9), the Earth ethic is characterised as anthropocentric despite clearly embracing the biota with whom we are ‘fellow-voyagers’. On the other hand, even though so-called ‘tautological anthropocentrism’ – the fact that our valuing is ‘human’ valuing – is dismissed as a ‘hollow claim not worth making’ (10), this seems to be precisely the sense in which the Earth ethic is indeed ‘anthropocentric’, for it is framed precisely so that it does not ‘overwhelm our [human] capacity’.

Of two more substantial points, the first is not so much a criticism as a suggestion for an alternative ending to Callicott's reflections. Callicott chides Dale Jamieson – a trifle unfairly, I feel – with responding to the problem of global climate change by a seemingly unadventurous resort to virtue ethics or a combination of virtue ethics and utilitarianism (288). Unfairly, inasmuch as Callicott himself, following in the footsteps of Leopold, looks initially for inspiration to Ezekiel and to the Gaia concept of the earth as a living organism – which, conceptually speaking, might be judged to be little more than a re-hash of Stoicism.

But perhaps what is wrong is precisely to conceive of global climate change as presenting a ‘colossal moral problem’. To appeal, for a moment, to the quieter version of Stoic thinking represented by Epictetus, we are advised to get hold of a jug by the handle by which it can be carried. The question then is by what handle we can get hold of the problem of global climate change. And frankly, colossal moral problems are in one sense just too big to carry. Failure to address the problem, for example, must bring colossal guilt in its train. On the other hand, even a colossal moral problem is still a moral problem and, as Callicott himself intimates more than once, there are ways of framing the climate change problem which ‘vastly exceed the temporal parameters of ethics – any ethic’ (235). As we have seen, his eminently judicious solution is to constrain our focus to the ‘Holocene climate and the biota that is adapted to it’ (298). But even so constrained, if we fail to protect the future of human civilisation and of those with whom we are ‘fellow-voyagers’, to speak of this as a moral failure seems hardly to cut the mustard. Perhaps the soubriquet ‘moral’ is thought to deliver ‘clout’. I doubt it does that, and am more inclined to heed the wise words of Bill Shankley, former manager of Liverpool football club, who, taunted over his enthusiasm for the game and conceding that it was not ‘a matter of life and death’, declared it to be ‘much more serious than that’ (Sunday Times (UK) October 4^th 1981). Moral failures – sins – are by and large thought of as forgiveable, provided that we are sufficiently penitent. Failure of the scale envisaged, on the other hand, would be, quite simply, unforgiveable. Furthermore, and extending Leopold's threefold division of virtue ethics, the charge would be laid at the door not simply of individuals, nor their practices, nor their societies, but at the door of humanity itself. This wears more the aspect not of a colossal moral failure but of a colossal failure of imagination, buttressed it may be by collective folly, myopia and even insanity.

The second point arises from Callicott's observation that the holistic tendency of the land ethic reverses the general tendency of ethics towards an individualistic emphasis. He comments, with some justice, that this ‘may be because the basic structure of biotic communities is very different from that of human communities’ (64). He then proposes to resolve the potential tensions arising from this difference by appealing to a nested hierarchy of responsibilities accompanied by a prioritising strategy which gives precedence to stronger and more intimate responsibilities over weaker and more impersonal ones. It might be objected, however, that far from describing a solution, this simply describes the problem. For – the objector might continue – the stark, if unpalatable, truth is that it is precisely the strong and intimate ties that pose the threat. Nature cares not a fig for the individual, whereas in human morality the individual is paramount. Thus it is not human immorality but human morality that is ‘out of step’, and that accounts in large part for the pressures that we place on the planet. To be sure, to abandon our reverence for the individual is unthinkable. But if we do not at least radically rethink our views about what this requires, then we may indeed be destined to tread the unforgiveable path.

Engagingly written, Thinking Like a Planet has much more to offer than there has been space to register here. This is no perfunctory rehearsal of previous work. The extensive review of the idea of a ‘science of ethics’, for example (chs 4 & 5), helps to achieve a substantial consolidation both of Callicott's Humean reading of Leopold and of the viability of an ethic rooted in an evolutionary-ecological worldview. Furthermore, and ancillary to this purpose, his understanding of moral beings as ‘relationally defined and constituted’ enables him to deliver some well-aimed and telling blows at Peter Singer's ‘impartiality’ doctrine – the idea that equal weight should be given to the like interests of all those whom the actions of a moral agent may affect (124–126, 289–292). In the polyphony that constitutes environmental ethics over the past half-century, Baird Callicott's has been an unmistakeable and invaluable voice. Locating and articulating as it does a defensible and feasible focus for environmental concern in the face of global climate change, this book proves that it still is.