With this post, PEL introduces a new feature: Extended excerpts from recent and forthcoming books on philosophy and related topics.

Imagine a hypothetical argument between two philosophers—a self-described empiricist and a faithful Augustinian. Let’s grant that they have the same basic conception of how to reason. They start with premises that they deem to be true and important, and they attempt, when drawing implications, to rely as firmly as possible on the truth of the foundational premises. Having them begin with different premises, we can expect that they will end in different places. The empiricist tells you that to be an empiricist you must begin with the premise that all knowledge is based on the senses. The Augustinian tells you that nothing else, like, say, the sensed world, is all that real when compared to God. How will you choose between these paths?