Wittgenstein, Praxeology, and Frege’s Three Realms
Wirth Conference on What Is Austrian In Austrian Economics
Mississauga, Ontario, 17-18 October 2008
Roderick T. Long
Department of Philosophy
The Kingdom of the Father is spread out upon the earth, and men do not see it.
– Gospel of Thomas §113
1.Frege, Mises, and the Three Realms
The crucial link between Austrian economist Ludwig von Mises and Austrian philosopher Ludwig Wittgenstein lies in their shared commitment to the anti-psychologistic project inaugurated by the (German) logician Gottlob Frege (1848-1925), by whom both men were influenced – Wittgenstein directly, and Mises indirectly via Husserl.1
In his 1918 article “Thought” (the first of his three Logical Investigations), Frege distinguishes among three kinds of items. First, there are the items of the outer realm, which are both public (they “have no owner,” and so are equally accessible to different observers) and sensible (capable of being perceived via the senses); Frege instances physical, empirically knowable objects such as trees. Second, there are the items of the inner realm, which are private (both in the sense of having an owner, i.e. belonging to a particular subject, and in the sense of not being directly knowable except by that subject) and not sensible; these are psychological items which Frege calls “ideas” or “presentations.” Finally, there are those items that are easily but wrongly confused with presentations, namely the items of the third realm, which are public but not sensible; Frege calls these “thoughts,” and has in mind not psychological states
1 Frege’s influence on Wittgenstein is extensive and uncontroversial. The extent of Frege’s influence on Mises, via Husserl, is more difficult to ascertain, but it was Frege’s critique of Husserl’s Philosophy of Arithmetic that converted Husserl from psychologism to anti-psychologism, and Mises cites Husserl’s later work Logical Investigations favourably (Ludwig von Mises, Epistemological Problems of Economics, trans. George Reisman (New York University Press, 1976), p. 23, n. 27) precisely for its critique of psychologism.
R. T. Long – Wittgenstein, Praxeology, and Frege’s Three Realms – p. 1