Passing by these contentions as unmeaning or irrelevant and seeing nothing but irreconcilable contradiction between the conceptions of the world as immutable law and a self-determining subject pragmatism (q.v.) seeks other means of vindicating the reality of freedom. It agrees with older forms of libertarianism in taking its stand on the fact of spontaneity as primary and self-evidencing, but it is not content to assert its existence side by side with rigidly determined sequence. It carries the war into the camp of the enemy by seeking to demonstrate that the completely determined action which is set over against freedom as the basis of explanation in the material world is merely a hypothesis which, while it serves sufficiently well the limited purpose for which it is devised, is incapable of verification in the ultimate constituents of physical nature. There seems in fact nothing to prevent us from holding that while natural laws express the average tendencies of multitudes they give no clue to the movement of individuals. Some have gone farther and argued that from the nature of the case no causal explanation of any real change in the world of things is possible. A cause is that which contains the effect ("causa aequat effectum"), but this is precisely what can never be proved with respect to anything that is claimed as a real cause in the concrete world. Everywhere the effect reveals an element which is indiscoverable in the cause with the result that the identity we seek for ever eludes us. Even the resultant of mechanical forces refuses to resolve itself into its constituents. In the "resultant" there is a new direction, and with it a new quality the component forces of which no analysis can discover.[16]