Bad models with interesting physics and vice versa: Some comments on the Casetti and Isard-Liossatos papers

Abstract

We have before us in two papers by Professor Casetti and Professors Isard and Liossatos two highly ambitious models, ambitious in broad class of phenomena about which they wish to enlighten us. If their ambitions are high, then we cannot doubt that they would want our expectations to be equally high. Inevitably, one is led to ask: have they succeeded or failed in meeting these expectations? I will argue that they have both failed. My daughter constructs models with her Lego set and brings them forward for my judgment, as Professors Casetti, Liossatos, and Isard have just done for ours. Often, a touch reveals that they are jerry-built. More and more frequently of late, I find a solid structure and much reality of detail. She has improved her modelbuilding capabilities. The criteria I use to judge her models are obvious to both me and her. A great personal disappointment to me in my perusal of regional science literature is lack of such criteria by which to judge our own models, of more or less accepted ways of applying pressure to models proffered to us to see if they work. We simply don' t have such criteria; reason for this lack is not that they are unavailable but that we have elected, for reasons that I do not understand, not to apply them. What criteria can we apply when judging a model? M.S. Bartlett [1, p. 124] submits three that seem uncontroversial to me. A model is deemed successful, he says, the extent to which: (i) known facts are accounted for; (ii) greater insight and understanding are achieved of biological situation being studied; (iii) theory or model can correctly predict future pattern, even under [and I would add, especially under] different conditions from those pertaining to current observed data. I think it time to demand of models and theories introduced in these sessions