ARE WE LOST IN THE VALE OF IGNORANCE OR ON THE MOUNTAIN OF PRINCIPLE

Making progress in understanding global and long-run problems raised b y human perturbations of ecological systems, and in making that unders tanding relevant to policy formulation, will require intense collabora tion between, at least, ecologists and economists. There is far too li ttle of this now and far too much fairly fruitless argument and lectur ing-in part because each side seems embarrassed by its lack of ability to do what it claims needs to be done. Ecological models cannot predi ct the long-run changes in the multiple functions of natural systems t hat might follow from human actions such as land clearance or waste st orage. Economists' valuation techniques cannot convincingly deal with multiple dimensions of change in the environment or with the non-use v alues of any changes. An ecological-economic modeling project of 20 ye ars ago reveals a few lessons for those who would like to see progress on collaborative research ultimately aimed at correcting these defici encies. For example, real collaboration requires investment of substan tial up-front time, investment best made in the context of a mathemati cal model of the problem to be investigated. The model forces particip ants to fit their ideas together rather than to string them out indepe ndently. It also will likely force compromise from disciplinary purity . There is much to be said for using such projects to train a small gr oup of Ph.D.s who will have observed and participated in the collabora tion. The existence of such a group will do more for ''eco-system valu ation'' than ad hoc and episodic forums involving old dogs, even thoug h some of these would be happy to learn new tricks.