The same arguments would apply to the structural tensors of curvature of the continuum, namely, to

, to

and to

. If the continuum is amorphous, these structural tensors, together with the

’s that compose them, are meaningless until we have decided upon some theoretical type of congruence of geometry; and even then they represent characteristics of structure that are as conventional as the geometry we have selected. But if, on the other hand, a definite metrics exists in the continuum, then these structural tensors represent curvatures of the continuum, which we may regard as physically existent and no longer as purely conventional.

CHAPTER VIII
THE MEANING OF THE WORD RELATIVITY