Babylonia was the primary locus of Jewish learning for many centuries. The heads of the Babylonian academies of Sura and Pumbedita were called Gaon and were widely recognized as the preeminent scholars of their day. With this distinction came the authority to promulgate religious decisions for the community. Saadia was the the greatest Gaon of all times. He lived from 882 to 942 C.E., during the time that the Muslims ruled Asia Minor.
In Saadia's day, he sought to reconcile the philosophical perspective of Islam, to which Jews living in Islamic countries were exposed, with the Torah. Much of Islamic philosophy at this time was grounded in the thinking of Aristotle and Plato, and so Saadia wrote about this, as well. His most famous book is entitled "The Book of Beliefs and Opinions" and it was written originally in Arabic, later translated into Hebrew by the Ibn Tibbon family. In this book, Saadia attempts to reconcile Judaism with the philosophical thinking of Aristotle and Plato, his goal being to bring assimilated Jews back to Torah and halakhah. Saadia accept the notion that reason is a legitimate standard for truth and set out to demonstrate that the Torah is compatible with philosophical reason. Jewish religious beliefs, according to Saadia, pass the test of reason. What is more, Saadia contended, the Torah is the finest source of truth available and the study of Torah further develops one's rational judgment.
In addition, Saadia wrote the first Arabic translation of the Bible, which included commentaries and grammatical notes. He also wrote the first Hebrew dictionary, and a book about Hebrew grammar. Muslims at this time were involved in Arabic language and grammar studies and Saadia hoped to inspire Jews to explore their own religious roots more deeply. Moses Maimonides said of Saadia, "If not for our master Saadia Gaon, Torah would have been forgotten in Israel."
In Saadia's day, one of the most significant threats to Jewish life came from the Karaites, a group whose origins lay in the Jewish community, but who had separated from the Jewish community in opposition to rabbinic Judaism. The Karaites maintained that the laws of the Talmud were not obligatory upon Jews because they were written not by God, but by the rabbis. The Karaites claimed that only the Torah comes from God and it, alone, should serve as the basis of Jewish authority and life. Traditional Judaism has always maintained that the Talmud is the Torah she'b'al peh (the Oral Torah, given at Sinai but transmitted orally for much of our history until it was finally written down in the academies of Babylonia). Saadia defended rabbinic authority against the claims of the Karaites, going so far as to declare that they were not Jews.
1. The laws of the Torah can be divided into two groups. The first set encompasses those laws which human reason immediately identifies as necessary for human society, such as the prohibition against murder. Such laws are common-sense. The second set of laws, however, are far less obvious and their purpose often eludes people. Included among these are Shabbat observance, kashrut, and the laws of family purity. Saadia tells us that if we examine these laws closely we will discover that they do, in fact, yield benefits for individuals and society, though sometimes these benefits are not immediately apparent. As an example, abstaining from work on holy days leads to more study and the development of family relationships.
2. Saadia maintained that human beings possess free will, the capacity to make choices about their behavior. Muslim philosophers at this time promoted the Kallam, a system of thought which denies the existence of free will as an allusion and even denies causality of events in the universe, ascribe all power and will to Allah. Saadia parted company with Muslim philosophers over the issue of free will, for several reasons. First, if God is the first and only cause in the universe, then there is no difference between the righteous and sinners; all do the will of God. Hence there is no difference between a righteous deed and a sin. Second, if God is fully in control of people's behavior, then it makes no sense to punish one who breaks the law, since s/he is merely doing the will of God. Finally and most importantly from a Jewish perspective, in a universe totally dominated by the will of God, mitzvot have no purpose or meaning, since people are incapable of "obeying" or "disobeying" them. There can only be a commandment if there is someone capable of accepting the commandments. In an effort to emphasize the role of free will in Jewish thinking, Saadia placed great emphasis on the covenant made at Sinai, in which the Israelites freely obligated themselves to God. Hence Saadia maintained that God created us with free will, a concept that has always been central to Jewish thinking.