A Reader Asks About Fighting Sin With Sin

He writes:

Thanks for your tireless and faithful work; your writing’s had a tremendous influence on my thinking as a Christian - -especially your explanations of the problems of consequentialism.

Here’s a question for you, though:

I’m slowly working through some of the Fathers, and I’m on John Cassian’s Conferences. At one point, he suggests using sin against sin; that is, to use one’s pride (at being oh-so-holy in the eyes of others) as a way to keep from giving in to temptations of the flesh: I won’t engage in gluttony or fornication or what-have-you simply because I want to preserve my reputation with the folks around me.
(Here’s a relevant passage, right at the beginning of the link)

I’m wondering, though, how to square this with the imperative not to do evil that good might come of it.

I know that the writings of one saint aren’t dogmatic, but Cassian’s seems like good advice to me. (Something similar has worked for me in the past: To avoid being tempted by lustful thoughts, daydreams about Star Trek can do wonders—precisely because Star Trek can be an occasion of sinful idleness for me; it’s captivating. In other words, I’m replacing a more serious sin [since lust is an offense against another person] with a less serious one.) And yet it’s doing something that’s evil so that good might come of it.

I’m not sure how much sense I’m making, but I wanted to try to think through this. Any help would be welcome!

I think the thing to remember with St. John Cassian is that he is here writing as a pastor and shepherd (and, I might add, a very shrewd psychologist) and not as a dogmatic theologian, as you note. He is doing what good spiritual guides do: helping us spiritual weaklings do the best we can with what we have. The key, I think, is in the title: “How to make use of vainglory.” In other words, vainglory is not a sin to be cultivated, but a fact of life to be exploited for good as best we can. There’s a certain whimsy to what he writes, a kind of playfulness. Read it in that spirit. I don’t think it’s consequentialist at all. He’s not urging us to try to be vainglorious. He’s simply noting that since we tend to care about what people think of us (which is the peccadillo of vanity, not the grave sin of pride), we might as well use that energy to steer us away from more serious sin. But of course, the ultimate goal is to be neither vain nor lustful. Vainglory is the wind resistance the soul faces as it takes flight in the Spirit. It slows us down, but if we arch our wings right we can exploit it to fly higher.