I have posted previously about the different ways in which knowledge may be represented. A key learning of the discipline of Artificial Intelligence in its short life thus far is that not all representations are equal. Indeed, more precise representations may provide less information, as in this example from cartography (from a profile of economist Paul Krugman):
Again, as in his [Krugman’s] trade theory, it was not so much his idea [that regional ecomomic specializations were essentially due to historical accidents] that was significant as the translation of the idea into a mathematical language. “I explained this basic idea” – of economic geography – “to a non-economist friend,” Krugman wrote, “who replied in some dismay, ‘Isn’t that pretty obvious?’ And of course it is.” Yet, because it had not been well modelled, the idea had been disregarded by economists for years. Krugman began to realize that in the previous few decades economic knowledge that had not been translated into [tractable analytical mathematical] models had been effectively lost, because economists didn’t know what to do with it. His friend Craig Murphy, a political scientist at Wellesley, had a collection of antique maps of Africa, and he told Krugman that a similar thing had happened in cartography. Sixteenth century maps of Africa were misleading in all kinds of ways, but they contained quite a bit of information about the continent’s interior – the River Niger, Timbuktu. Two centuries later, mapmaking had become more accurate, but the interior of Africa had become a blank. As standards for what counted as a mappable fact rose, knowledge that didn’t meet those standards – secondhand travellers’ reports, guesses hazarded without compasses or sextants – was discarded and lost. Eventually, the higher standards paid off – by the nineteenth century the maps were filled in again – but for a while the sharpening of technique caused loss as well as gain. ” (page 45)
Larissa MacFarquhar : The deflationist: How Paul Krugman found politics. The New Yorker, 2010-03-01, pp. 38-49.