I have to start by dispelling misunderstandings to which my title may give rise. In the first place, it is not suggested that Menger, if anybody, has to bear the blame for the incompleteness of the subjectivist movement, and there are few pioneers in the history of thought to whom it is given to witness the completion of what they have set in motion. Secondly, I have to confess that I know of no criterion that would permit us to decide whether a movement of thought has reached its 'end' and is thus 'complete'. Subjectivism has in this century been extended from human preferences to expectations. In years to come it may be extended to the interpretation of so-called information. What, then, does its incompleteness at Menger's time signify?
In this paper I am concerned with certain features of Menger's work which appear to have prevented him from carrying his subjectivist intentions quite as far as, in the light of the later development of the train of thought he set in motion, might have been possible; in other words, with certain obstacles to his subjectivist mode of thought that he failed to surmount.
At the Menger Symposium in 1971, Professor Hayek characterized the style of Menger's subjectivism in a memorable passage:
Menger believes that in observing the actions of other persons we are assisted by a capacity of understanding the meaning of such actions in a manner in which we cannot understand physical events. This is closely connected with one of the senses in which at least Menger's followers spoke of the 'subjective' character of their theories, by which they meant, among other things, that they were based on our capacity to