This chapter describes the works shown in A World Where Many Worlds Fit, an exhibition from 2008 to 2010 that presented activist art made in the context of anti-globalisation protests against neoliberalism. The essay examines the political presuppositions of the ‘movement of the movements,’ as the alter-globalisation movement came to be known in the mid-2000s. It explores the presumptions and blind spots of workerist post-politics and contrasts this to contending viewpoints and critiques. In the concluding passages, the essay briefly explores Henri Lefebvre’s writings on the state from the 1970s and proposes that biopolitical protest is not merely opposed to the state but is also a feature of its self-revolutionising, a process that is radically open to transformation.

Accounts of building collapses at Venice and Beauvais help to demonstrate that structural failures can occur through changes in soil (perhaps in the level of the water table) or masonry (from mortar shrinkage or stone decay). Stabilisation works carried out on the tower at Ely by the author have involved removal of nineteenth century external straps, corner tie bars (possibly unnecessary) and grout forming a solid core encircling the inner wall surface and reinforced by rods inserted through the outer wall surface. The vibration and cracking of towers due to bell-ringing are potentially significant, as are the effects of wind; square solid towers intended as pinnacles can be overturned by the wind if they are too tall. The development of cracks in both solid walls and square hollow towers can be explored using simple equilibrium approaches to find the angles at which the walls and towers lean enough to first crack and later be overturned. Cracks appear in walls at smaller angles of leaning than in comparable thin-walled towers, but overturning occurs at rather greater angles for walls than for towers.

Various structural elements have construction methods and potential problems that deserve attention. Points of note include: the ‘ratchet effect’ on rubble-filled walls of repeated freezing and thawing; the possibility of mortar shrinkage or of stone decay through excessive stress; the crucial role of crossing piers which carry a tower, and how they can be strengthened (as at Milan and Worcester); the (maybe counterintuitive) structural contribution of pinnacles; the detailed actions of flying buttresses, and how they may fail (as at Amiens) if they are not ‘flat arches’; the importance of binding ribs to walls by single ‘through-stones’; how stone windows handle thrusts from the wall above and wind outside, starting with rectangular windows and moving on to rose windows; and the actions in response to live and dead loads on cantilevered stone stairs, whether piecewise straight with corner landings or geometrical (as in a round tower). Calculations about structural actions (of flying buttresses, stone windows and stone stairs) can be based on simple statics.

Unlike an arch, a dome can be thought of as a thin shell, with forces acting smoothly within its surface. It is then treated as if the minimum thickness is set mainly to avoid local buckling. The compressive stress required to support the dome is independent of the thickness, for the dome as for other thin shells, such as cones. However, the thickness is often combined with the stress in the ‘stress resultant’ of membrane techniques. The techniques demonstrate that tensile stresses can develop near the base of the dome. If its supports move, a hemispherical dome can crack into orange-like segments along lines from its base towards its crown. It can be assembled from such notional segments. Opposite segments paired at their crown as ‘arches’ can be analysed separately to find the minimum thickness. From the use of ‘arches’ for complete domes comes the use of slices for incomplete domes, which have lost some adjacent segments. The results show that complete domes can be thinner than incomplete ones. There remain difficulties, though: in a dome that has (say) eight sides, stresses focussed on the ribs between the sides need analysis.

The chapter ‘Vanguardia’ explores the growing body of literature on social practice art. Through reviews of books by Gerald Raunig, BAVO, Gregory Sholette, Oliver Ressler, Grant Kester, Critical Art Ensemble, Nato Thompson, Yates McKee, Mikkel Bolt Rasmussen and Rebecca Gordon-Nesbitt, the chapter examines how various strands of contemporary leftist culture put into practice forms of radical culture that at the same time address the totality of the global capitalism. Alternative tactics and strategies, such as reformism, dialogue, education, protest and revolution, account for different perspectives on the left and different possibilities for the avant garde today.

‘The only game in town’ poses the acute problem of class struggle in relation to identity politics. Contemporary political campaigns like Black Lives Matter and MeToo transform the experience of victimisation directly into demands for accountability, a process that tends to reproduce the political and structural frameworks within which structural violence takes place. Against ‘victim politics,’ I argue for a democracy without guarantees that rejects various solutions to the rise of the political right: masochistic self-culpabilisation, appeals to civil society, scapegoating and nihilistic destruction. I examine Marxist literature for concepts with which to break with the postmodern liberalism that prevents the emergence of a radical left universalism.

The chapter addresses new possibilities for thinking about avant-garde art and vanguard politics by reviewing recent debates between Slavoj Žižek and McKenzie Wark on the Anthropocene, and further, by examining the limits of cultural revolution as we have known it since the late 1960s. The impasse of Occupy Wall Street and similar protest movements has led Žižek to shift from a view of the political party in terms of Jacques Lacan’s psychoanalytic Discourse of the Analyst towards reflections on the Discourse of the Master. The consequent critiques of Žižek that are examined are shown to have evaded his ideas and fail to adequately address his Hegelian-Lacanian approach to dialectical materialism. On the other hand, one finds that Žižek’s renewal of radical politics is challenging others on the progressive left to do the same.

Geometry and proportion have always been fundamental to expertise in building; they emerge even in the record of constructing a great temple in the biblical book of Ezekiel. The books on architecture of the Roman author Vitruvius were copied widely and fed directly into the secrets of the medieval lodges, which are now known in part from Villard de Honnecourt’s sketchbook. The disputes at Milan about how to proceed with the cathedral illustrate how the time-honoured rules of proportion persisted, even though their intuitive justifications appeared to be getting lost. Ultimately, Renaissance thinking and the invention of printing opened a new era. This is well represented by St Paul’s Cathedral but also gave rise to the distinction between engineers and architects and the belief that every gentleman with money and a copy of Vitruvius could design his own buildings.

‘Beyond Socially Enraged Art’ proposes that the task of cultural revolution is to redefine today’s political struggles in class terms. Through Alain Badiou’s study of the Chinese Cultural Revolution as well as Régis Debray’s analysis of guerrilla struggle in Cuba, the chapter provides a working model for recent efforts to unite socially engaged artists, as occurred at the January 2015 symposium of Artist Organisations International.

The magazine Adbusters sparked a massive national and worldwide social movement against neoliberal economic policy and global capitalism. The question of whether the Occupy Wall Street encampments would make one demand to the US President or several demands led to a broad popular discussion of class inequality. OWS exposed the phenomenon of class polarisation, which reacts to structural problems in contradictory ways. Such contradictions are shown to be at work in the new forms of post-revolutionary and post-political horizontalism, pointing to both the potential and limits of OWS.

Idealised assumptions are made about masonry: it has zero tensile strength, unlimited compressive strength and zero sliding. These assumptions allow calculations about masonry structures that equilibrate and accommodate small changes in boundary conditions. Such small changes produce cracks that in an arch form ‘hinges’ through which the line of thrust passes. With four or more hinges, large loads make the arch collapse as the line of thrust strays outside it; a ‘flat arch’, whose abutments can be joined by an internal straight line, does not collapse. To keep the line of thrust within it, an arch must have at least a minimum thickness. The ratio of the actual thickness to this minimum is the ‘geometrical factor of safety’. Often it exceeds 2, but by the so-called ‘safe’ theorem, if it exceeds 1 then the arch is safe. New cathedral buildings have collapsed within two decades, a typical period for soil settlement. Later collapses may be due to changes in the soil or the masonry. Without evidence of recent shifts, cracks are just responding to previous change, and should merely be filled with mortar to keep them dry.