At the recent debate among Republican presidential candidates, Chris Matthews asked the candidates to raise their hands if they believed in evolution. Sen. Sam Brownback didn’t raise his hand. Last week he published an op-ed in the New York Times explaining his position.
The senator makes some very sensible points, most importantly that “evolution” can name several quite different doctrines. It may mean, for example, “microevolution, small changes over time within a species,” which the senator accepts, but also “an exclusively materialistic, deterministic vision of the world that holds no place for a guiding intelligence,” which he rejects. And there are, of course, quite a few doctrines intermediate between those two as well.
But the senator also offers some general observations on the relationship between faith and reason that I find worrying. He writes:
The scientific method, based on reason, seeks to discover truths about the nature of the created order and how it operates, whereas faith deals with spiritual truths. The truths of science and faith are complementary: they deal with very different questions, but they do not contradict each other because the spiritual order and the material order were created by the same God.
Senator Brownback thus distinguishes faith and reason on the basis of subject matter , for in his view “they deal with very different questions”¯faith treats “the spiritual order,” and reason “the material order.” This, however, is obviously wrong. For some people, of course, it’s a matter of faith that God created the world in six days about six thousand years ago; but it’s nevertheless knowable by natural science that this is not the case. Similarly, many people believe in faith that God exists, but Catholics hold (and Senator Brownback is a Catholic) that this proposition can be known by reason in philosophy. Hence, the subject matters of faith and reason in part overlap.
The distinction between faith and reason, correctly understood, is based not on a difference in subject matter but on a difference in epistemological warrant, that is, on the kinds of reasons a person may have for assenting to a particular proposition. On this view, a person holds a proposition in faith if he believes the proposition because he thinks it has been revealed in history by God¯for example, on Mount Sinai through Moses or on the shores of the Lake of Tiberias by Jesus Christ. A person holds a proposition as a matter of reason if he thinks he has for that proposition the kinds of arguments properly accepted in a discipline such as natural science or philosophy, neither of which accept arguments based on purported divine revelation. Any one proposition, therefore, may be divinely revealed, or be knowable by reason in science or philosophy, or both of these, or even neither.
To say that there is no conflict between faith and reason, therefore, is to say that the propositions one holds to be divinely revealed do not contradict the propositions knowable according to the standards of science or philosophy. Whether this is really the case depends, obviously, on just which propositions one thinks were divinely revealed and which are knowable in science or philosophy. If it turns out that a proposition one holds in faith is contradicted by a proposition known by reason, then one must either rework one’s theology, giving up on the idea that God revealed the proposition in question, or else show that the scientific or philosophical arguments that contradict that proposition are in fact inconclusive by scientific or philosophical standards.
Also, it’s quite possible for one person to hold a proposition as a matter of faith while another holds the same proposition as a matter of reason. Take the existence of God. I think the philosophical argument for the existence of God is very strong, and so I think I know by reason that God exists. Other people, either because they don’t think the argument is very strong or perhaps because they’ve never studied philosophy, may believe in faith that God exists without knowing it by reason. Furthermore, it’s possible that there are some propositions that have been divinely revealed on which science and philosophy are simply silent, such as whether there are three persons in God. So too it’s possible that there are some propositions on which divine revelation is silent but about which science or philosophy can teach us much, such as whether copper is a good conductor of electricity or whether universals exist independent of the particulars that instantiate them.
Senator Brownback, as I said, is a Roman Catholic, but his view of faith and reason is not the one generally upheld in the Catholic tradition. The traditional view, the one I’ve described here, derives from Thomas Aquinas and has never been better explained than in a very short and beautifully written book by Etienne Gilson called Reason and Revelation in the Middle Ages 
Finally, note that Senator Brownback’s never-the-twain-shall-meet understanding of faith and reason runs into other serious problems too. Consider this:
Faith supplements the scientific method by providing an understanding of values, meaning and purpose. More than that, faith ¯ not science ¯ can help us understand the breadth of human suffering or the depth of human love.
It’s right that natural science doesn’t tell us anything about values, meaning, and purpose, but philosophy surely can, and it’s just ridiculous to think that human reason, as in Shakespeare, doesn’t teach us about suffering or love. To relegate normative questions to the realm of faith would be to deny the existence of an objective morality knowable by human reason¯and in this way the virtues, natural law, and human rights become indistinguishable from whatever putative divine commands any crackpot may say he has lately received. This is not a view that anyone, especially someone involved in public life, should want to defend.
Robert T. Miller is an assistant professor at the Villanova University School of Law.
