Nevertheless, our mind, in alliance with omnipotent habit, has, with the assistance of some strained interpretation, given to the combination of phenomena in the segment of universal life that is accessible to us, a certain kind of harmony and unity, and this from time immemorial has gained repute under the name of an intelligible explanation of the created world. But the known, which is the familiar, world is sufficiently unintelligible to make good faith require of us that we should accept unintelligibility as the fundamental predicate of being. It is impossible to hold, as some do, that the only reason why we do not understand the world is that something is hidden from us or that our mind is weak, so that if the Supreme Being wished to unveil the secret of creation to us, or if the human brain should so much develop in the next ten million years that he will excel us as far as we excel our official ancestor, the ape, then the world will be intelligible. No, no, no! By their very essence the operations which we perform upon reality to understand it are useful and necessary only so long as they do not pass a certain limit. It is possible to understand the arrangement of a locomotive. It is also legitimate to seek an explanation of an eclipse of the sun, or of an earthquake. But a moment comes--only we cannot define it exactly--when explanations lose all meaning and are good for nothing any more. It is as though we were led by a rope--the law of sufficient reason--to a certain place and left there: 'Now go wherever you like.' And since we have grown so used to the rope in our lives, we begin to believe that it is part of the very essence of the world. One of the most remarkable thinkers, Spinoza, thought that God himself was bound by necessity. Let any one probe himself carefully, and he will find that he is not merely unable to think but almost unable to live without the hypothesis of Spinoza. The work of Hume, who so brilliantly disputed the axiom of causal necessity, was only half done. He clearly showed that it is impossible to prove the existence of necessary connection. But it is also impossible to prove the contrary. In the result, everything remained as before: Kant, and all mankind after him, has returned to Spinoza's position. Freedom has been driven into an intellectual world, an unknown land, 'from whose bourne No traveller returns,'