The solution to a problem P is a function of the set of constraints C đ P. Here we will write S(P) and by that designate the solution, or solutions, to the particular problem P. In equation 1 P(x) are successive problem formulations. P(0) is a problem formulation from which a solution can be obtained. In the ideal case it is either identical to the problem it represents or otherwise accurate enough as to pick out a solution that is also a solution to the problem.
What does this tell us about interdisciplinary problem solving? Before we attempt to answer this question we shall make an assumption: most problem solving work takes place in the explorative first phaseâas Simon once put it, âthere is merit to the claim that much problem solving effort is directed at structuring problems, and only a fraction of it at solving problems once they are structuredâ (Simon 1973, 187). That is, the explorative phase often takes up more resources and time than the derivative phase. We can therefore adumbrate problem solving in phase-2 rather briefly.
Interdisciplinarity in Phase-2
Suppose we have an interdisciplinary problem (i.e. a problem to which several disciplines have some contribution to make) P. Assume that in P phase-2 has been reached. Then it is the case: (a) that the set of constraints C of P is fully, or sufficiently, understood; and (b) that P is considered to be worth solving by members of all of the disciplines involved (i.e. D is met).
Intuition then suggests that the specific tools at the disposal of different disciplinesâwhat Bechtel (1986) calls the cognitive tools (theories, methods, models, etc.)âare brought to bear on the issue at hand.
Examples of this kind of problem may involve producing explanations of complex phenomena where, for instance, different causes âbelongâ to the domains of different disciplines. A homely example for the sustainability scientist would be problems relating to explaining changes in the climate system. Here the underlying causes of the kinds of event one is interested inâsuch as the gradual warming of mean surface temperature over the past century, or changes in the chemical composition of the atmosphereâbelong to the domains of a range of different disciplines.
There are issues specific to phase-2. For example, to what extent do the disciplines need to overlap, and in what sense do they need to be different if the interdisciplinarity is to be genuine? However, here those problems will be put to one aside. Instead we shall move on to focus on the first phase of problem solving.
Interdisciplinarity in Phase-1: The âstandardâ model
Two general arguments can be made for the potential benefits of interdisciplinarity in this part of the process. One relies on adding constraints (or providing more precise ones) in order to narrow the solution space; the other concerns the revision, or sometimes subtraction, of constraints in order to obtain, say, a more broadly valid, or in other words more robust, solution.