The term "revelation" is used in two senses in Jewish theology; it either denotes (1) what in rabbinical language is called "Gilluy Shekinah," a manifestation of God by some wondrous act of His which overawes man and impresses him with what he sees, hears, or otherwise perceives of His glorious presence; or it denotes (2) a manifestation of His will through oracular words, signs, statutes, or laws. In Judaism, issues of epistemology have been addressed by Jewish philosophers such as Saadiah Gaon (882–942) in his Book of Beliefs and Opinions; Maimonides (1135–1204) in his Guide for the Perplexed; Samuel Hugo Berman, professor of philosophy at the Hebrew University; Joseph Dov Soloveitchik (1903–1993), talmudic scholar and philosopher; Neil Gillman, professor of philosophy at the Jewish Theological Seminary of America, and Elliot N. Dorff, professor of philosophy at the American Jewish University. One of the major trends in modern Jewish philosophy was the attempt to develop a theory of Judaism through existentialism. One of the primary players in this field was Franz Rosenzweig. His major work, "Star of Redemption", expounds a philosophy in which he portrays the relationships between God, humanity and world as they are connected by creation, revelation and redemption. Conservative Jewish philosophers Elliot N. Dorff and Neil Gillman take the existentialist philosophy of Rosenzweig as one of their starting points for understanding Jewish philosophy. (They come to different conclusions, however.) Rabbinic Judaism, and contemporary Orthodox Judaism, hold that the Torah (Pentateuch) extant today is essentially the same one that the whole of the Jewish people received on Mount Sinai, from God, upon their Exodus from Egypt. Beliefs that God gave a "Torah of truth" to Moses (and the rest of the people), that Moses was the greatest of the prophets, and that the Law given to Moses will never be changed, are three of the Thirteen Principles of Faith of Orthodox Judaism according to Maimonides. Orthodox Judaism believes that in addition to the written Torah, God also revealed to Moses a set of oral teachings, called the Oral Torah. In addition to this revealed law, Jewish law contains decrees and enactments made by prophets, rabbis, and sages over the course of Jewish history. Haredi Judaism tends to regard even rabbinic decrees as being of divine origin or divinely inspired, while Modern Orthodox Judaism tends to regard them as being more potentially subject to human error, although due to the Biblical verse "Do not stray from their words" ("Deuteronomy 17:11) it is still accepted as binding law.