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PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
or his paving of new ways in historical analysis by the use of ge- 
neral explanatory categories, typical examples being the notions of 
enormity and mimesis. But the main inspiration of ARNOLD TOYNBEE 
is, I believe, the area of forecasting: he is deeply worried about the 
present trends of the world, and he tries to tell what will happen 
if we do not understand things better and take action accordingly. 
Well, to repeat, my point is not to defend or criticize historical 
views; what I want to emphasize is that the distinction between 
>xplanation and forecasting is of crucial relevance in history as in 
any other science. 
How about economics? Here the distinction between fact-finding 
and forecasting is well recognized, and in some areas of economics 
the explanatory models are reliable enough to be successfully exploi- 
ted for purposes of forecasting. Areas where the techniques of 
forecasting have been successful include demand analysis, production 
analysis, cost analysis, and on the whole the key areas of micro- 
economics, In macroeconomics, on the other hand, we are still in 
the beginnings in the transition from explanatory models to forecast- 
ing models, and, to return to the starting point, the theme of our 
Study Week is a challenge to assess the present status about valid 
model building in the areas of economic growth and business cycle 
analysis. 
From the general point of view of scientific method, model 
building is a pluralistic endeavour. Science can be regarded as a 
collection of models: meteorological models, economic models, histo- 
rical models, etc. And in each science there is a plurality of models: 
short range models, long range models; we have purely theoretical 
models, integrated theoretical-empirical models, all sorts of models. 
Science is not a unified system which embraces everything; it is a 
myriad of different approaches, partly consistent with each other, 
partly inconsistent, and each approach takes the form of a model. 
The pluralism is often to distinct advantage. À case in point is the 
Eastern and Western approaches towards economic growth. It is 
a question whether it would at all be meaningful to construct an inte- 
erated model to cover both the Eastern and Western types of long 
1] Stone - pag. 04