One last point is worth noting. We have seen that there were ten gravitational equations, and that there were ten
’s whose values were to be determined. Owing to the fact that there were as many equations as unknowns, it might be thought that one single set of values for the ten
’s would be obtained. But inasmuch as the values of the
’s deduced from
must necessarily differ as we choose one mesh-system or another, it would appear as though some definite mesh-system were imposed on us—a fact incompatible with the arbitrariness of mesh-system demanded by the general theory of relativity. According to relativity, there should be, therefore, a fourfold arbitrariness in the values of the