Abstrakt
During his long career, Gottlob Frege held that truth (and falsehood) is indefinable. G.
E. Moore and Bertrand Russell, for a considerable period, also adhered to this primitivist view.
All three employed a cryptic 'treadmill' argument from vicious circularity in order to demonstrate that any attempt to define truth is impossible. My primary goal is to reconstruct this argument.
There are two doctrines that must be taken into account. First, we must consider the redundancy (or, following Dummett: equivalence) thesis about truth.
Second, there is a specific epistemological view which I call 'the doctrine of judgment' that had come to the adherents of the primitivism as a positive influence of Kant. If this doctrine is omitted, the circularity argument and the associate doctrine of truth-primitivism cannot be properly interpreted and seems unintelligible or even mysterious.
In reference to Frege, I shall explain that the doctrine of judgment is a sequential model of knowledge-that. Its function and importance will be shown in a formal exposition of the treadmill.
The proposed interpretation of the treadmill, as I shall show, has serious consequences for the ongoing debate about Frege's conception of judgment. Contrary to a recently published view of Wolfgang Künne, it will be explained that judgment is an epistemic act by means of which we acquire a knowledge-that rather than mere putting forward a thought with a commitment to its truth.