2. Interfaces between spheres

Analyses for sustainability must focus attention on the interfaces, the interactions and the interdependencies between the economic, social and environmental spheres, on the characterization of principles of performance and quality in each sphere, and on the principles of rights, respect or responsibility proposed for one sphere in relation to another. The political sphere has the role of the ‘‘referee’’ that arbitrates in relation to the different – and often incompatible – claims made by the actors of the social and economic sphere for themselves and with regard to the other spheres (including the environmental sphere).

If we consider interfaces between each pair of ‘‘spheres’’ (that is, two different ‘types’ of organization), then with the four spheres there are six pairings. In Fig. 1, these are portrayed as the ‘‘edges’’ of the tetrahedron. We may also use a simple 4 X 4matrix array to present the facets of analysis, as in Table , in which the diagonal cells evoke performance concepts and criteria that relate principally to a single organizational form, and the off diagonal cells signal performance concepts and criteria arising as ‘‘interferences’’ of two organizational forms.

 The interface aspects can be characterized through investigation of the ‘‘claims’’ or ‘‘demands’’ made by each sphere relative to the others. Systems analyses focus on the roles, services or behaviour that is needed of, expected of, or sought by one sphere from each of the other spheres, in order to permit its ‘‘good functioning’’. This requires not just biophysical and economic modelling but also analyses with explicit anthropological, symbolic and moral dimensions that highlight the reasons, meanings, principles and purposes attached to these demands or expectations. In particular, in explaining the functioning of the political sphere, it is necessary to investigate the justifications emanating from the social and economic sphere for this or that principle of need, respect or responsibility for any one sphere in relation to another.

In reality, of course, many issues involve ‘‘cumulative causation’’ with the interference of all four organizational forms. In a fundamental sense, it is meaningless to treat any sphere or interface in isolation from the others (e.g., the economic and political are inseparable from the social, and the economic cannot exist without the environmental, etc.).The restriction to a pair-wise classification of interfaces is didactic but artificial. For analytical purposes, it is convenient to highlight as complementary:

(1) descriptions centred on the internal functioning of each sphere having a degree of autonomy relative to the other spheres;

(2) descriptions of interactions between two spheres. Through following a sequence of binary links, we can build up examples of ‘‘causal pathways’’ of influence ramifying through the whole system.

In Table 1, we present some of the distinctive features of the four spheres and their six interfaces. The rest of this short paper discusses, with reference to existing themes in the literature, some options and conventions for application of this ‘‘Tetrahedral Model’’ in sustainability science and policy analyses.

 Table 1: The Four Spheres and their interfaces