Is string theory a theory of quantum gravity?

Some problems in finding a complete quantum theory incorporating gravity are discussed. One is that of giving a consistent unitary description of high-energy scattering. Another is that of giving a consistent quantum description of cosmology, with appropriate observables. While string theory addresses some problems of quantum gravity, its ability to resolve these remains unclear. Answers may require new mechanisms and constructs, whether within string theory, or in another framework.Comment: Invited contribution for "Forty Years of String Theory: Reflecting on the Foundations," a special issue of Found. Phys., ed. by G 't Hooft, E. Verlinde, D. Dieks, S. de Haro. 32 pages, 5 figs., harvmac. v2: final version to appear in journal (small revisions

Public squares as a means of integrating economy, environment and society in British city centres

Sustainable Development is invariably epitomised by economy, environment and society represented as three equal sized rings in symmetrical interconnection. This assumes a separation, even autonomy, and detracts from the fundamental connections. Much debate is now centred on how to integrate these sectors, rather than seeking trade-offs between them. Up to the 20th Century, public squares, offered clear examples of this integration as they are representative of the values of the society that created them. There are numerous examples from different time periods in a variety of cultures. In the second half of the 20th Century, British cities experienced increasing competition for space, which partly led to domination by market economies. As city centres became commodities, more devices were employed to attract consumers. One of the most significant was the indoor shopping centre. As malls were constructed over city streets, increasingly public space became privatised. The public sector is now experiencing substantial decline and the balanced model of economy, environment and society has been grossly distorted. Social capital may be a means of regaining equilibrium. This paper will demonstrate the significance of squares in sustaining vibrant communities; and consider mechanisms for their re-introduction as a means of contributing to the integration of economy, environment and society

Black holes in the quantum universe

A succinct summary is given of the problem of reconciling observation of black hole-like objects with quantum mechanics. If quantum black holes behave like subsystems, and also decay, their information must be transferred to their environments. Interactions that accomplish this with `minimal' departure from a standard description are parameterized. Possible sensitivity of gravitational wave or very long baseline interferometric observations to these interactions is briefly outlined.Comment: 11 pages + ref