t of existence on the best possible
grounds. "Know, my masters," he writes, "that no man should believe
anything that is not attested by one of these three sanctions:--rational
proof as in mathematical science, the perception of the senses, or
traditions from the prophets and learned men." His biographer in the
monograph "Maimonides," published by the Jewish Publication Society of
America[5], expresses his further views on the subject in compendious
form, and then gives his final conclusion as follows:

"'Works on astrology are the product of fools, who mistook
vanity for wisdom. Men are inclined to believe whatever is
written in a book, especially if the book be ancient; and in
olden times disaster befell Israel because men devoted
themselves to such idolatry instead of practising the arts of
martial defence and government.' He says, that he had himself
studied every extant astrological treatise, and had convinced
himself that none deserved to be called scientific. Maimonides
then proceeds to distinguish between astrology and astronomy,
in the latter of which lies true and necessary wisdom. He
ridicules the supposition that the fate of man could be
dependent on the constellations, and urges that such a theory
robs life of purpose, and makes man a slave of destiny. 'It is
true,' he concludes, 'that you may find strange utterances in
the Rabbinical literature which imply a belief in the potency
of the stars at a man's nativity, but no one is justified in
surrendering his own rational opinions because this or that
sage erred, or because an allegorical remark is expressed
literally. A man must never cast his own judgment behind him;
the eyes are set in front, not in the back.'"

While Maimonides could be so positive in his opinions with regard to a
subject on which he felt competent to say something, he was extremely
modest with regard to many of the great problems of medicine. He often
uses the expression in his writings, "I do not see how to explain this
matter." He quotes with approval from a Rabbi of old who had counselled
his students, "teach thy tongue to say, I do not know." In this, of
course, he has given the best possible evidence of his largeness of mind
and his capacity for making advance in knowledge. It is when men are
ready to say, "I do not know," that progress becomes possible. It is
very easy to rest in a