Note 148 — Introductory material
Reading edition
Although this axiom is à priori, its application to the measurement of actual bodies, as we found in discussing Helmholtz's views, always involves an empirical element[156]. Our axiom, then, only supplies the à priori condition for carrying out an operation which, in the concrete, is empirical—just as arithmetic supplies the à priori condition for a census. As this topic has been discussed at length in Chapter II., I shall say no more about it here.