Let us now call to mind a truth, the fullest and most thorough proof of which will be found in my prize essay on the freedom of the will—the truth that on account of the absolutely universal validity of the law of causality, the conduct or the action of all existences in this world is always strictly _necessitated_ by the causes which in each case call it forth. And in this respect it makes no difference whether such an action has been occasioned by causes in the strictest sense of the word, or by stimuli, or finally by motives, for these differences refer only to the grade of the susceptibility of the different kinds of existences. On this point we must entertain no illusion: the law of causality knows no exception; but everything, from the movement of a mote in a sunbeam to the most deeply considered action of man, is subject to it with equal strictness. Therefore, in the whole course of the world, neither could a mote in a sunbeam describe any other line in its flight than it has described, nor a man act any other way than he has acted; and no truth is more certain than this, that all that happens, be it small or great, happens with absolute _necessity_. Consequently, at every given moment of time, the whole condition of all things is firmly and accurately determined by the condition which has just preceded it, and so is it with the stream of time back to infinity and on to infinity. Thus the course of the world is like that of a clock after it has been put together and wound up; thus from this incontestable point of view it is a mere machine, the aim of which we cannot see. Even if, quite without justification, nay, at bottom, in spite of all conceivability and its conformity to law, one should assume a first beginning, nothing would thereby be essentially changed. For the arbitrarily assumed first condition of things would at its origin have irrevocably determined and fixed, both as a whole and down to the smallest detail, the state immediately following it; this state, again, would have determined the one succeeding it, and so on _per secula seculorum_, for the chain of causality, with its absolute strictness—this brazen bond of necessity and fate—introduces every phenomenon irrevocably and unalterably, just as it is. The difference merely amounts to this, that in the case of the one assumption we would have before us a piece of clockwork which had once been wound up, but in the case of the other a perpetual motion; the necessity of the course, on the other hand, would remain the same. In the prize essay already referred to I have irrefutably proved that the action of man can make no exception here, for I showed how it constantly proceeds with strict necessity from two factors—his character and the motives which come to him. The character is inborn and unalterable; the motives are introduced with necessity under the guidance of causality by the strictly determined course of the world.