Before religion as we understand the term, there was animism, which was based on the idea of an enchanted universe. Every river, every tree, and every stone was thought to be populated by spirits. The world was mysterious, capricious, unpredictable, and uncontrollable. Then came the various polytheistic religions, like those of the Babylonians, the Egyptians, and the Greeks. Each of these religions posited divine beings—sometimes immortal, sometimes not—who involved themselves in the daily workings of nature, creating storms and earthquakes, turning humans into stags, and so on. Then appeared the great religions of the East, Hinduism and Buddhism, followed by the three great monotheistic religions, Judaism, Christianity, and Islam.

Of these, only one—Christianity—was from the beginning based on reason. Judaism and Islam are primarily religions of law; there is a divine lawgiver who issues edicts that are authoritative both for nature and for human beings. In the case of Judaism these edicts apply mainly to God’s chosen people, the Jews. In the case of Islam they apply to everyone. In both cases, however, the laws are divinely revealed and humans must follow them. Both Jews and Muslims may engage in extensive debates, but these are confined to the best way to interpret and apply the written codes. Christianity, by contrast, is not a religion of law but a religion of creed. Christianity has always been obsessed with doctrine, which is thought to be a set of true beliefs about man’s relationship to God.

Philosopher Ernest Fortin writes that while the highest discipline in Judaism and Islam is jurisprudence, the highest discipline in Christianity is theology. The Christian theologian is charged with employing reason to understand the ways of God. There are no theologians in Hinduism and Buddhism because human beings are not called to investigate God’s purposes in this manner.