We must also show that while the rational soul makes use of the data of sense perception, which are corporeal, as the occasions for the formation of its general ideas, it is not wholly dependent upon them, and the sense data alone are inadequate to give the soul its intellectual truths. Empirical knowledge is inductive, and no induction can be more general and more certain than the particular facts from which it is derived. As all experience, however rich, is necessarily finite, empirical knowledge is never universally certain. But the soul does possess universally certain knowledge, as for example the truths of mathematics and logic; hence the origin of these truths can not be empirical. How does the soul come to have such knowledge? We must assume that there is a divine emanation cleaving to the soul, which stands to it in the relation of light to the sense of sight. It is to the illumination of this intellectual substance and not to the data of sense perception that the soul owes the universal certainty of its knowledge. This divine substance is the Active Intellect. As long as the soul is united with the body, perfect union with the Active Intellect is impossible. But as the soul becomes more and more perfect through the acquisition of knowledge, it cleaves more and more to the Active Intellect, and this union becomes complete after death. Thus the immortality of the soul is proved by reason. It is based upon the conviction that the soul is an immaterial substance and that its perfection lies in its acquisition of intellectual ideas.[208]
Judah Halevi cannot help admitting the fascination such speculation exercises upon the mind of the student. But he must warn him against being misled by the fame of such names as Plato and Aristotle, and supposing that because in logic and mathematics the philosophers give us real proofs, they are equally trustworthy in metaphysical speculation. If the soul is, as they say, an intellectual substance not limited in place and for this reason not subject to genesis and decay, there is no way to distinguish one soul from another, since it is matter which constitutes individual existence. How then can my soul be distinguished from yours, or from the Active Intellect and the other Intelligences, or from the First Cause itself? The souls of Plato and Aristotle should become one so that the one should know the secret thoughts of the other. If the soul gets its ideas through divine illumination from the Active Intellect, how is it that philosophers do not intuit their ideas at once like God and the Active Intellect, and how is it they forget?
Then as to their ideas about immortality. If immortality is a necessary phenomenon due to the intellectual nature of the soul and dependent upon the degree of intellectual knowledge it possesses, how much knowledge must a man have to be immortal? If any amount is sufficient, then every rational soul is immortal, for everybody knows at least the axioms of logic and mathematics, such as that things equal to the same thing are equal to each other, that a thing cannot both be and not be, and so on. If a knowledge of the ten categories is necessary, and of the other universal principles which embrace existence conceptually, though not practically, this knowledge can be gotten in a day, and it is not likely that a man can become an angel in a day. If on the other hand one must know everything not merely conceptually but in detail, no one can ever acquire universal knowledge and no one is immortal The philosophers may be excused because this is the best they can do with the help of pure reason. We may commend them for their mode of life in accordance with the moral law and in freedom from the world, since they were not bound to accept our traditions. But it is different with us. Why should we seek peculiar proofs and explanations for the immortality of the soul, since we have promises to that effect whether the soul be corporeal or spiritual? If we depend upon logical proof, our life will pass away without our coming to any conclusion.[209]
Judah Halevi takes issue also with the Mutakallimun. These, as we know, were Mohammedan theologians who, unlike the philosophers, were not indifferent to religion. On the contrary their sole motive in philosophizing was to prove the dogmas of their faith. They had no interest in pure speculation as such. Judah Halevi has no more sympathy with them than with the philosophers. Owing to the fact that the Karaites were implicit followers of the Kalam and for other reasons, no doubt, more objective, he thinks less of them than he does of the philosophers. The only possible use, he tells us, of their methods is to afford exercise in dialectics so as to be able to answer the arguments of unbelievers. To the superficial observer the Mutakallim may seem to be superior to the prophet, because he argues, whereas the latter affirms without proving. In reality, however, this is not so. The aim of the Mutakallim is to acquire the belief which the prophet has by nature. But his Kalam may injure his belief instead of confirming it, by reason of the many difficulties and doubts it introduces. The prophet, who has natural belief, teaches not by means of dialectic discussion. If one has a spark of the true belief in his nature, the prophet by his personality will benefit him by a slight hint. Only he who has nothing of true belief in his nature must have recourse to Kalam, which may benefit him or injure.
Judah Halevi follows up this general comment by a brief sketch of the system of the Kalam, but we need not enter into this matter as there is little there that we do not already know, and there is no detailed criticism on the part of Judah Halevi.[210]
The Rabbi concludes his discourse with the king of the Chazars by declaring his intention to leave the land in order to go to Jerusalem. Although the visible Shekinah is no longer in Palestine, the invisible and spiritual presence is with every born Israelite of pure heart and deed; and Palestine is the fittest land for this communion, being conducive to purity of heart and mind.[211]
[B] This simile represents Halevi's thought. He does not use this expression.