R. Isadore Twersky, "Some Non-Halakic Aspects of the Mishneh Torah" in R. Alexander Altmann ed., Jewish Medieval and Renaissance Studies, pp. 114-115:
In common with many medieval writers, Jewish, Christian, and Muslim, Maimonides is of the opinion that Jews in antiquity once cultivated the science of physics and metaphysics, which they later neglected for a medley of reasons, historical and theological. He does not, however, repeat the widespread view, as does Halevi, that all sciences originated in Judaism and were borrowed or plagiarized by the ancient philosophers. Halevi, echoing a Philonic view, states: "...The roots and principles of all sciences were handed down from us first to the Chaldeans, then to the Persians and Medes, then to Greece, and finally to the Romans." That Maimonides does not subscribe to this view of the Jewish origin of all wisdom has been inferred--a kind of argument ex silencio--from his formulation in the Guide, where he merely establishes the antiquity of philosophy per se. It seems to me that this is clearly noted by Maimonides in the introduction to his Commentary on the Mishnah where, in buttressing an argument, he says that this matter is known to us not only from the prophets but from the wise men of the ancient nations "even though they did not see the prophets or hear their words." Maimonides does not care to trace all philosophic wisdom back to an ancient Jewish matrix. His sole concern is to establish hokmah as an original part of the Oral Law, from which it follows that study of the latter in its encyclopedic totality--that is, gemara--includes philosophy. This is the position--a harmonistic position unifying the practical, theoretical and theological parts of the Law--which Maimonides codified in the Mishnah Torah.
 Moreh Nebukim, I, 71. See Wolfson, Philo, I, 163.
 Kuzari, II, 66.
 Kapah, p. 42. See Teshubah, V, 5.