Abstract In this essay, I will lay out first in some detail the exegetical principles implicit in Augustine's treatment of an early apparent conflict between Scripture and the findings of “sense or reason.” Then I will analyze Galileo's two major discussions of the issue, first in his Letter to Castelli, and then in his Letter to the Grand Duchess, touching on Foscarini's ill-fated Letter in between. I will turn then to an internal tension that many commentators have perceived within the exegetic principles that Galileo deploys in meeting the theological challenge to Copernicanism. The tension was, broadly speaking, between two rather different strategies for dealing with that challenge. According to the more radical choice, the strategy would be to deny the relevance of Scripture to our knowledge of the natural world. The more conservative strategy would be to allow that the authority of divine revelation extended to passages in Scripture describing features of the natural world but also to admit that where this description clashed with something that could be demonstrated through “sense or reason,” an alternative to the literal, everyday, meaning of the Scripture passage should be sought. This latter proviso would imply that even in this, the most conservative, approach, theology is not being given absolute priority over natural philosophy.