Another argument against free will is that it is irreconcilable with God's knowledge. If man alone is the master of his choice, God cannot know beforehand what he will choose. And if God does know, the man cannot but choose as God foreknew he would choose, and what becomes of his freedom? This may be answered by saying that the knowledge of a thing is not the cause of its being. We do not determine a past event by the fact that we know it. Knowledge is simply evidence that the thing is. So man chooses by his own determination, and yet God knows beforehand which way he is going to choose, simply because he sees into the future as we remember the past.[200] Judah Halevi's discussion of the problem of freedom is fuller than any we have met so far in our investigation. But it is not satisfactory. Apart from his fourfold classification of events which is open to criticism, there is a weak spot in the very centre of his argument, which scarcely could have escaped him. He admits that the will is caused by higher causes ending ultimately in the will of God, and yet maintains in the same breath that the will is not determined. As free the will is removed from God's control, and yet it is not completely removed, being related to him by a chain of causes. This is a plain contradiction, unless we are told how far it is determined and how far it is not. Surely the aspect in which it is not determined is absolutely removed from God's control and altogether uncaused. But Judah Halevi is unwilling to grant this. He just leaves us with the juxtaposition of two incompatibles. We shall see that Hasdai Crescas was more consistent, and admitted determinism. We have now considered Judah Halevi's teachings, and have seen that he has no sympathy with the point of view of those people who were called in his day philosophers, _i. e._, those who adopted the teachings ascribed to Aristotle. At the same time he was interested in maintaining that all science really came originally from the Jews; and in order to prove this he undertakes a brief interpretation of the "Sefer Yezirah" (Book of Creation), an early mystic work of unknown authorship and date, which Judah Halevi in common with the uncritical opinion of his day attributed to Abraham.[201] Not to lay himself open to the charge of inconsistency, he throws out the suggestion that the Sefer Yezirah represented Abraham's own speculations before he had the privilege of a prophetic communication from God. When that came he was ready to abandon all his former rationalistic lucubrations and abide by the certainty of revealed truth.[202] We may therefore legitimately infer that Judah Halevi's idea was that the Jews were the originators of philosophy, but that they had long discarded it in favor of something much more valid and certain; whereas the Greeks and their descendants, having nothing better, caught it up and are now parading it as their own discovery and even setting it up as superior to direct revelation.