In this paper, we investigate a relation between the history of western logic and religion. Logic, as distinct from theology, began in Greece in the sixth century B. C. After running its course in antiquity, it was again submerged by theology as Christianity rose and Rome fell. Its second great period, from the eleventh to the fourteenth centuries, was dominated by the Catholic church, except for a few great rebels, such as the Emperor Frederick II(1195-1250). This period was brought to an end by the confusion that culminated in the Reformation. The third period, from the seventeenth century to the present day is dominated by science; traditional religious beliefs remain important but are felt to need justification, and are modified wherever science seems to make this imperative.