From qotd:

Moshe ben Maimon was born at Cordoba, Spain on this day in 1135, at a time when that portion of Spain was under Moorish rule. The family fled to Morocco after Cordoba was captured by a far less tolerant Islamic dynasty, and Moshe studied at the university at Fez. He was free to write and study because his younger brother was a gem merchant, but after the brother was lost at sea Moshe became a physician. After living briefly in Israel, he settled at Cairo and became the physician to the Sultan Saladin. He was a Jewish rabbi who lived almost his entire life in Muslim communities, wrote philosophy and medical treatises in Arabic, and is best known by a Greek name, Maimonides.

Do not consider it proof just because it is written in books, for a liar who will deceive with his tongue will not hesitate to do the same with his pen.

Truth does not become more true by virtue of the fact that the entire world agrees with it, nor less so even if the whole world disagrees with it.

Be convinced that, if man were able to reach the end without preparatory studies, such studies would not be preparatory but tiresome and utterly superfluous.

Consequently he who wishes to attain to human perfection, must therefore first study Logic, next the various branches of Mathematics in their proper order, then Physics, and lastly Metaphysics.

Further, there are things of which the mind understands one part, but remains ignorant of the other; and when man is able to comprehend certain things, it does not follow that he must be able to comprehend everything.

The soul is subject to health and disease, just as is the body. The health and disease of both … undoubtedly depend upon beliefs and customs, which are peculiar to mankind.

– Moshe ben Maimon (Maimonides), 1135–1204

en.wikipedia.org/wiki/Maimonides