 We could, of course, use an alternative measurement method of t, say one resting upon an axiom \(\psi\) of T, to gain evidence for the axiom \(\phi\) being true in some selected instances. This move, however, only shifts the problem to applications of another axiom of T. For these applications the same type of difficulty arises, viz., mutual dependency of the semantic values of \(\psi\) and t. We are thus caught either in a vicious circle or in an infinite regress when attempting to gain evidence for the propriety of a single measurement of a theoretical term. Sneed (1979: ch. II) was the first to describe that particular difficulty in the present manner and termed it the problem of theoretical terms. Measurement of the force function in classical mechanics exemplifies this problem well. There is no method of measuring force that does not rest upon some law of classical mechanics. Likewise, it is impossible to measure temperature without using some law that depends upon either phenomenological or statistical thermodynamics.