The Role of Minimalism in Art and Science

The intensity of disagreements among modern students of ecology and evolution suggests that the problems being posed may be too complex. In analogous situations in the arts, "minimalism," a deliberate search for the simplest manifestation of problems has been useful. A study of the ecology and evolutionary constraints on the particularly simple metazoans, hydras, is presented as an example of a minimalist approach. I define the idea of "richness" of theories and suggest that rich theories are to be preferred, even though they may not be superior to more limited theories in their entire predictive domain. One rich mathematical theory asserts that hydras alter reproductive rate and body size as functions of the total food supply and the size distribution of food particles, and that there is an optimal food particle size for each genotype. This theory implies that the constraint surface for hydras can be represented in three dimensions as a series of surfaces, rather than a single surface predicted by a less rich theory. The validity of the multiple-surface model cannot be tested directly by laboratory data for statistical reasons. It can, however, be tested by field distribution data free of these statistical problems. This example suggests that the current polemics may be resolved by focusing on the clearer predictions of competing theories rather than on the statistically ambiguous portions of their predictive domains.