 |
 |
"Summarising the argument: modelling something involves (at least) 3 steps: (1) the map from evidence to the model (2) inference within the model (proof or running it) and (3) the interpretation back to what is observed. If strengthening step (2) (e.g. simplifying the model to obtain proof) leads to the critical weakening of (1) and/or (3) then you end up with a weaker total chain and the attempted strengthening is counter-productive overall." Not everyone agrees with this inferential approach to model building. E.g. Einstein talking about physical models, but applies more widely: "Physics constitute a logical system of thought which is in a state of evolution, whose basis cannot be distilled, as it were, from experience by an inductive method, but can only be arrived at by free invention. The justification (truth content) of the system rests in the verification of the derived propositions by sense experiences. The skeptic will say: 'it may well be true that this system of equations is reasonable from a logical standpoint. But it does not prove that it corresponds to nature'. You are right, dear skeptic. Experience alone can decide on truth." (Quoted in Kaldor 1972 p.1239.) Sorry Peer, we've wander off your initial request a little...! Dan Olner School of Geography University of Leeds