Odd choice for a date, one would have thought — an evening of robust debate about pornography. Still, there they were: couples, boy and girl, sitting neatly and expectantly in the chairs provided by the Middle East for this past Friday night’s event. There was a higher concentration of testosterone at the back of the club — the usual lurkers, prowlers, and sniffers — but the total demographic was more Coldplay than AC/DC.

Sponsored, fittingly somehow, by Rock Star Energy Drinks, the “Porn Debate” was blowing through Cambridge between dates in Pittsburgh and New York City. The hook was clear: for our edification and amusement, a porn star and a pastor were going to have it out. Ron Jeremy, hero to two generations of wankers, was the porn star; Craig Gross, co-founder of the online anti-porn ministry XXXChurch.com, was the priest. Standard set-up: two lecterns, one moderator, two 15-minute opening statements, then questions from the audience answered in three minutes, with 90 seconds of rebuttal. And a lot more bang for your buck than Mitt Romney versus Tommy Thompson.

Neither of the debaters, it should be said at the outset, is an intellectual force: their polemics are not rigorous or particularly logical, their grammar is poor, and their lines — with a few exceptions — are un-memorable. What they both have by the bucketload, however, is sincerity: Jeremy sincerely wants to defend the industry that has been so very good to him, and Gross sincerely wants the porn-consuming man-in-the-street to wake up to the consequences of his actions, his attitudes, his mouse-clicks.

Physically, they are a perfect mismatch. Tubby Ron, with the soft eyes and the pampering voice, is a creature of orgiastic sleekness, nearly amphibious from a lifetime of lo-fi swinging. “I’ve made a promise to myself and my friends,” he said, musing for a moment on his porn-gotten gains, “that one day I will do something magnanimous.” Gross is young enough to be Jeremy’s son, skinny, and boy-band handsome, his hair gelled in interesting directions and his speech jumping with California spazziness. Asked by an audience member if religion had perhaps done more harm, historically, than pornography, he replied, “All I can say? I’m sorry. You know? God, Jesus, the whole bunch there have a bunch of bad spokesmen on their behalf. That’s not what I’m about.”

Even the most sentimental of sexual revolutionaries would have trouble denying that pornography, in the year 2007, is on something of a downward spiral. Not commercially, of course: piped like Muzak into the best hotels, and riding high on billion-dollar DVD sales, porn may be experiencing its commercial Age d’Or. But, uh, morally. Like any stimulant, porn’s natural tendency is toward desensitization, and with users googling one-handed for ever-nastier thrills, the industry has been doing its humble best to keep up.

Gapers, cream pies, DPs, ATMs (and that’s not automated teller machines); Houdini-like feats of bondage; epic degradations; there are things on the Net that, once seen, will cause you to get barked at by dogs for the next two weeks. The average man is porn-afflicted, in a steady condition of masturbatory burnout. And the average woman — well, in the post-porn world there are no average women, only MILFs, nymphos, tiny-titted teens, and lesbian cheerleaders. We seem to be headed for some kind of showdown with reality. Either we get a grip, brothers, or we go down forever, melted to our chairs in an exploding All-Starlet Ass-Fuck Bonanza. Who will be our guide?

Here, perhaps, is the reason for the success of the Porn Debate: the kids want answers. The crowd was attentive and non-partisan: Jeremy was greeted like an old friend — an old friend whom you have watched having sex — but his opponent was respectfully heard, and not booed or pilloried, even when he mentioned “God’s plan.”

Most interesting, as the debate progressed, was the manner in which the porn star ceded not the moral high ground but the low ground of reality to the pastor. Gross talked about the destruction of women; Jeremy soothed it away. “For every girl who’s having a problem,” he said, “I can show you a hundred thousand who’ve done quite well.” Gross read aloud from the back of a DVD: “Here at Pure Filth Productions, we believe in giving you the most hard-core rectum-wrecking anal scene possible. See these whores get pounded by enormous cocks until you’re wondering if they’re going to need adult diapers for the rest of their lives.” Jeremy winced and murmured that “niche marketing” comprises only a fraction of the adult industry.

Gross talked about addicts, casualties, brokenness. Jeremy, oily as a budget restaurateur, wove images of “happy recreational users” to whom porn (along with lingerie, exotic dancing, and travel to Hawaii or Mexico) is merely “a little boost to their sex lives.” In an elegant reversal, it was the veteran of hard-core who was being soft-core, squeamish, and airbrushed, and the goofy unworldly Christian who was insisting on a full close-up. “It’s a scam,” concluded Gross. “I’ve seen these girls at the conventions, how they turn it on for the cameras, how they allow themselves to get mauled. It’s a scam. You’re being scammed.”