Non-Bayesian decision theory ante litteram: the case of G. L. S. Shackle

This paper deals with the intellectual environment in which George L. S. Shackle’s theory of decision making was formulated and first discussed. Shackle’s approach had a great impact on decision theory in late 1940s and early 1950s being the single formalised attempt to discard the probability framework in the description of behaviour under uncertainty - a goal shared by Knight and Keynes. Against Shackle, Arrow defended the use of probability theory in decision making, by denying that the Knightian distinction between risk and uncertainty had any behavioural significance, and paving the way to Savage’s Foundations of Statistics as the new mainstream reference. Through an assessment of the reception of Shackle’s theory the paper presents the way a number of theoretical economists, psychologists, and mathematicians were interested in the viability of a formally structured alternative to theories of behaviour using probability statements to describe uncertainty. The paper aim to show that the lively but concentrated discussion on alternative decisional criteria Shackle was part of is crucial to understand the multifarious developments observed in modern decision theory in the last twenty years or so. Indeed, as discussed in a twin paper by Basili and Zappia, Shackle’s theory was a much more viable alternative to subjective expected utility than both its contemporary critics and modern decision theorists have recognised.