The participants took the title seriously – “architecture.” Most authors are architects, some are architectural critics. The architects are of two kinds – two philosophies, two methodologies, two approaches to international institutions. One kind – the “true” architects – design complete integral systems, whole systems, leaving nothing out. They need no supplementary structures.

By “whole systems” I mean structures to cover all gases, all nations, all industries, all uses, and institutions that endogenize all incentives. The residual role of government is to enforce the rules; and the rules specify emission quotas and markets for purchase and sale of unused quotas. All the parts hang together. They are intellectually satisfying; they leave nothing out. There is a potential vulnerability here: if part of the system fails the rest may fail with it. But it all fits together economically and even aesthetically.

The second “architectural” approach, which I would not characterize as architecture but the authors do and I yield to their terminology, provides a set of substantially independent principles. The principles fit together with some completeness, but what I find to be their most attractive character is that the individual principles can stand alone, they have “separability”; if one fails it doesn't collapse a structure. The argument for each principle – the virtue of each principle – is independent of the arguments for the others.

Most of the complete architectures – the holistic, integral architectures – are dual, a domestic regime and an international. But the two display identical principles.