One of two philosophy courses I took at LSU was "Christian Philosophy", taught by an old family friend who happens to be a leading Farrer scholar (a fact I only recently learned). The other course was "Introduction to Philosophy", PHIL 1001, which was also officially known by another, one-word name - "Logic". So it is with some sense of divine serendipity and personal appreciation for Austin Farrer (and Dr. Ed Henderson) that I post this quote I've been saving for a while from the Philosopher's most famous article (emphases mine):
It would certainly be impertinence to suggest that the scholars who established the Q hypothesis reasoned falsely or misunderstood their own business; no less an impertinence than to talk of the great Scholastics so. St. Thomas understood the business of being an Aristotelizing Augustinian, and if I am not his disciple, it is not because I find him to have reasoned falsely. It is because I do not concede the premisses from which he reasoned. And if we are not to be Streeterians, it will not be because Dr. Streeter  reasoned falsely, but because the premisses from which he reasoned are no longer ours.Please note the mind of the philosopher on display, and never forget: Logical arguments always depend on whether we accept their first premisses.
Thus, christian and non-christian scholars have something in common - they both have to decide at what point to start from. :)