  The nature of the metric field, that is the nature  of the metric everywhere, is the same and is, therefore,  absolutely determined. It reflects according to Weyl, the a  priori structure of space or spacetime. In contrast, what is  posteriori, that is, accidental and capable of continuous  change being causally dependent on the material content that fills  space, are the mutual orientations of the metrics at  different points. Hence, the demarcation between the \(a\)  priori and the a posteriori has shifted, according  to Weyl: Euclidean geometry is still preserved for the infinitesimal  neighborhood of any given point, but the coordinate system in which  the metrical law assumes the standard form  \(ds^{2} =\sum^{n}_{i=1}(dx^{i})^{2}\) is in general different from place to place. 