ABSTRACT
To cope with a large number of different agents, it is necessary to abstract from the processes of individual decision-making or at least to consider them in a highly simplified form. This necessity to simplify was confronted by Alchian (see section 1.1.3) in his example of a population of travellers setting out from Chicago: thousands of travellers without any foresight explore an environment where the selection criterion is the availability of gasoline stations. This example is easily translatable into the terms of heuristic problem solving (section 4.1.2), but it is not an individual decision-maker who performs the problem solving. The problem of finding a feasible route is solved by the whole population of travellers, and this happens in an extremely wasteful way: most of the travellers have to walk back to Chicago but some solve the problem of getting away from the city. The underlying heuristic of trial-and-error is clear enough: try everything; some will succeed.
