108 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 2: I therefore subscribe to Professor KooPMANS’ thesis that we should not try to freeze the meanings of the terms used in econometrics at this stage. I think it will be our experience here this week that as we discuss econometrics we shall learn, and as we learn the words we use will come to have different and somewhat sharper meanings ‘han they have now. I fear that we can bog ourselves down by attempting to clarify points of terminology. Science is groping, and as we grope we shall wish to change the meanings of the technical words we use. VIAHALANOBIS I should like briefly to make two points. First I shall remove the apprehensions of Dr. Koopmans; I agree that to try to define what 's East of West would be absolutely futile; but we may say a « macro-national » or « micro-national » or use such neutral terms. [ agree also with the points made by Professor LEONTIEF. It seems to me that what is a decision model or what is a forecasting model also nvolve the question of terminology. ; However, terminology is in one sense a procedural point. I do ‘eel that we should have some discussions regarding the objectives of model making. Whether the question of terminology is pursued or not I have no strong views; but even the present discussion indicates that some clarification of terminology would be useful. It is purely my own personal ignorance. I should like to understand clearly what is meant by such term as « objective », « neutrality », « forecasting model » or « decision model » and such things. What are the different ‘ypes of models in relation to different spheres of interest? I am not suggesting that we should be interested in only one type. I agree generally with the observations made by Professor FrISCH that even if we have decision in view by politicians or others, the role of the scientist is to keep a « neutral » mind in advising how those « objectives » may be attained. I do not see that « neutrality » is in any way destroyed by keeping certain « objectives » in mind. On that point I am in complete agreement. :] Stone - pag. 106