Selv Alfred Marshall - en af den neoklassiske teoris fædre - anerkendte den
matematiske metodes begrænsning. I en brevveksling med vennen A. L. Bow-
ley, der var en varm fortaler for anvendelse af matematik og statistik i den 0ko-
nomiske forskning, fra 1906 skriver Marshall: ”. I had a growing feeling in
the later years of my work at the subject that a good mathematical theorem
dealing with economic hypotheses was very unlikely to be good economics: and
I went more and more on the rules - 1) Use mathematics as a shorthand lan-
guage, rather than as an engine of inquiry. 2) Keep to them until you have
done. 3) Translate into English. 4) Then illustrate by examples that are impor-
tant in real life. 5) Burn the mathematics. 6) If you can’t succeed in 4), burn 3).
This last I did often”, Landreth & Colander (1994:290-91).
Vær varsom ved anvendelsen af den hypotetisk deduktive metode, kunne man
mâske sammenfatte Marshall holdning til. Teori er nok godt, men uden en em-
pirisk kobling, bliver den megen teoretisering let gold og virkelighedsfjern,7 om
end et sâdant forhold kan være endda særdeles gavnlig for forskerens egen vi-
denskabelige karriere. Her er Keynes helt pâ linie med sin gamle lærer. Ogsâ
han advokerede for, hvad Landreth & Colander (1994:463) har benævnt for en
realytic approach: ”A realytic theory is contextual; it blends inductive informa-
tion about the economy with deductive logic. Reality guides the choice of as-
sumptions”. I sit biografiske essay om Thomas Malthus kommer Keynes’ af-
standtagen til den ricardianske deduktive videnskabelige approach sâledes klart
frem: ”. that ... the complete domination of Ricardo’s for a period of a hun-
dred years has been a disaster to the progress of economics”, hvorimod Mal-
thus derimod for Keynes fremstâr som den, der gav rammerne for: ”. formal
thinking to the complex confusion of the world of daily events . so as to pene-
trate these events with understanding by a mixture of intuitive selection and
7 Jf. eksempelvis den kritiske belysning af to moderne mikro0konomiske teoriretninger- ”rati-
onal choice”- og spilteorien - hos Beed & Beed (2000). En af formalismens farer er, som de
to forfattere pâpeger p. 181, hvis forstâelsen af den 0konomiske teori skulle ændre sig (har
ændret sig?) pâ en sâdan mâde, at termen ”’Theory’ is no longer seen as propositions purpor-
ting to describe, explain, or predict the real world. It is becoming schemata describing how
the real world might look is people behaved in the way the theory suggested. Economic theo-
ries describing how people actually behave are less common”.
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