The two postulates of relativity do not, in and of themselves, represent a complete theoretical system “in which the individual laws are implicitly contained and from which they can be found by deduction alone....” This point is tremendously significant; the special theory is predicated on two postulates and there is no reason to believe that all the conclusions that spring from that theory can be proven true by “deduction alone.” He went on: “For the time being we only have the kinematics of parallel translation