For at least two centuries most social thought has taken the earth to be the stable platform upon which dynamic social processes play out. Both climate change and the Anthropocene thesis – with their enfolding of dramatic geologic change into the space-time of social life – are now provoking social thinkers into closer engagement with earth science. After revisiting the decisive influence of the late 18th-century notion of geological formations on the idea of social formations, this introductory article turns to more recent and more explicit attempts to open up the categories of social thought to a deeper understanding of earth processes. This includes attempts to consider how social and political agency is both constrained and made possible by the forces of the earth itself. It also involves efforts to think beyond existing dependencies of social worlds upon particular geological strata and to imagine alternative ‘geosocial’ futures.

Recently, earth scientists have been discussing the idea of the 'Anthropocene' -a new geologic epoch defined by human geological agency. In its concern with the crossing of thresholds in Earth systems and the shift into whole new systemic states, the Anthropocene thesis might be viewed as the positing of a disaster to end all disasters. As well as looking at some of the motivations behind the Anthropocene concept, this article explores possible responses to the idea from critical social thought. It is suggested that the current problematization of planetary 'boundary conditions' might be taken as indicative of the emergence of a new kind of 'geologic politics' that is as concerned with the temporal dynamics and changes of state in Earth systems as it is with more conventional political issues revolving around territories and nation state boundaries: a geo-politics that also raises questions about practical experimentation with Earth processes.

Modern western political thought revolves around globality, focusing on the partitioning and the connecting up of the earth's surface. But climate change and the Anthropocene thesis raise pressing questions about human interchange with the geological and temporal depths of the earth. Drawing on contemporary earth science and the geophilosophy of Deleuze and Guattari, this article explores how geological strata are emerging as provocations for political issue formation. The first section reviews the emergence-and eventual turn away from-concern with `revolutions of the earth' during the 18-19 th C discovery of `geohistory'. The second section looks at the subterranean world both as an object of `downward' looking territorial imperatives and as the ultimate power source of all socio-political life. The third section weighs up the prospects of `earth system governance'. The paper rounds up with some general thoughts about the possibilities of `negotiating strata' in more generative and judicious ways.

The recent revival of the theme of hospitality in the humanities and social sciences reflects a shared concern with issues of belonging, identity and placement that arises out of the experience of globalized social life. In this context, migration -or spatial dislocation and relocation -is often equated with demands for hospitality. There is a need to engage more carefully with the 'proximities' that prompt acts of hospitality and inhospitality; to attend more closely to their spatial and temporal dimensions. Is the stranger or the Other primarily one who is recognisably 'out of place'? Or is there more to being estranged than moving from one territory to another? This brings us to the question of human finitude, and to the possibility of encounters with others that do not simply only occur in time or space, but are themselves generative of new times and spaces.

Early engagement with geoengineering by social scientists indicates a certain suspicion over the motives and modes of operation of scientific research in the field. In part, this reflects the prominence of the critique of the politics of emergency in recent social and political thought: a thematisation that links securitisation measures with foreclosures of the political. This paper turns the attention back on the social sciences, arguing that recent styles of ontological and political thought do not prepare us well for engaging with geologic issues in general, and geoengineering in particular. It is suggested that, rather than viewing geoengineering discourses and imaginaries as a retreat from politics, we might view them as playing an important role in opening up new kinds of politics oriented towards earth systems and their dynamics. This new 'geologic politics' involves a turn from issues hinging on territorial divisions of the earth's surface toward the strata that compose the deep temporal earth. As a political challenge, the question of how to live with dynamic and stratified earth systems not only promises to extend the scope of politics, but also points to the 'inhuman' limits of the political per se.