Calvin (curious): The TV listings say this movie has “adult situations.” What are “adult situations?” Hobbes (speculating): Probably things like going to work, paying bills and taxes, taking responsibilities… Calvin (dismayed): Wow. They don’t kid around when they say “for mature audiences.” Hobbes (puzzled): I’ve never understood how these movies make any money.

Ah yes, “adult” — as in “adult content” (violence, extramarital sex, cursing, etc.) and “adult movies” (more of the same, but more twisted) and “consenting adults” (they’ve got the right to do whatever they choose) and all that.

Has ever a word been more distorted? “Adult” is supposed to connote a grown-up, someone who shoulders steady responsibility and holds firm moral standards. Now it’s a rhetorical trump card played by people who can’t justify their behavior. Its implicit premise: Being an adult means you don’t need to justify anything to anyone any more.

It’s just another sign that we’re living in a culture of decadent self-indulgence. What always strikes me is how fundamentally childish this idea of adulthood is: No one can tell me what to do or not to do any more!

This is bad enough in a kid. It’s worse today because, in many ways, we’re encouraged to hang onto childish attitudes long past the point where we’re supposed to have grown up.

Consider college — for the majority of people, the first taste of life away from home.

On the academic side, universities have some requirements, and some students work not just to pass but also to excel. But that’s because they’re already motivated, not because the school held them to that standard. Many professors refuse to flunk any but the laziest pupil, so even the unmotivated can get by. (Some professors are pretty unmotivated themselves; teaching is a tiresome distraction from their real interests.) Students get so many second, third and fourth chances that they regard these as entitlements. (Some of them really should get second chances, if they’re trying and have potential. But the entitlement mentality doesn’t make those distinctions.)

Things get worse on the social side of campus life, where the culture is largely set by students themselves. It’s no secret what that’s produced — the binge drinking, the sexual hook-ups, the general frivolity. Now students widely assume that when they’re not in class, they’re free to devote themselves to whimsical self-indulgence, within the most minimal boundaries. Not every student buys into that culture, but those who don’t must work to avoid it, and may fall into it anyway.

Things weren’t always this way. Less than a century ago, universities held the in loco parentis ethic. Officials maintained the widely held standards of parents and actively involved themselves in students’ lives outside the classroom — overseeing activities, guiding choices, shaping character. They freely and regularly urged students to meet standards of honesty, industry, chastity and sobriety, often using biblical language. (“Behold now is the accepted time, behold today is the day of salvation,” wrote an early-20th-century dean in the University of Illinois student newspaper.)

In short, they made it clear that before students would be accepted as adults themselves, they’d have to earn it. (I wrote about this era in a previous column).

Alas, universities have long since abdicated that role. They’re not alone, for (again) the problem permeates the whole culture. Most advertising is a nonstop call to self-indulgence. Most media outlets give the impression that the good life as the affluent life. Most politicians get elected by promising to hand out goodies, all paid for with someone else’s money, including the money of future generations. Most credit-card companies — well, need we go on?

Just how this culture developed is a tale I’ll leave to sociologists. The most important thing is to recognize that we’ve got a problem. We’ve lost sight of what it means to be mature adults. Prodded by the social forces around us, we do what (being sinners) we hardly need any prodding to do: Whatever we want to do — not what we should do, or even what we should want.

So how does a Christian deal with this culture? One answer might be to opt out of it on a personal level: to say “I can’t do anything about anyone else, but I, at least, will live responsibly, upholding the kind of standards people had back when society more or less mirrored Christian standards.”

I’m afraid that approach is much too weak, for a couple of reasons.

The first and most important reason is that it neglects our duty to uphold standards to other people around us. Yes, on a certain practical level, we can’t stop them from boozing or sleeping around if they’re bound and determined to do so. But we’re obliged to at least take a shot at it, even at the risk of being perceived as a little in-your-face.

Let’s take an example. Say your college roommate likes to go out and get drunk. You don’t join him: You shake your head and say “no thanks, that’s not for me” — or even “that’s not for me because I’m a Christian.” Maybe you think you’re being humble and gentle, per Scripture. But the message he gets from you is the same one he gets from the culture: You do what you want and I’ll do what I want. You’re not helping him; you’re abandoning him. And if truth be told, in indulging his sin, you may be doing it out of a cowardly fear of confrontation. (“I have to live with this guy!”)

And that brings us to the second reason a merely personal approach to responsible living isn’t enough: It’s too weak a standard to sustain in your own life. It’s just too easy to get sucked into the culture of self-indulgence, too easy to slide into private sin because no one else is looking — and hey, this whole “mind your own business” ethic does have the advantage of helping you keep your shame secret, right?

Part of the solution lies in publicly declaring the standards you know are true and right. Of course you shouldn’t do good works before men in order to strut around feeling righteous. (Beware that temptation even if it isn’t originally your chief motive.) But you also shouldn’t keep your standards so quiet and personal that no one else knows about them. You should let people know what you believe — probably more than a few people, and probably more than just once.

Again, let’s take an example. Say you let it be known early on in college that you don’t believe in getting drunk. But over time, you’re tempted to join the party, if only for social reasons. You find yourself hoping people forget your original declaration as time goes by; you’re grateful when you drift out of your old social circles and meet new people, and you somehow don’t get around to repeating your stance to them. Maybe you even tell yourself “I’ll be a better witness if I’m just one of the guys — but that’ll have to wait a while, till I get established with them and the time is right.” From there on, the rationalization can take on a momentum of its own. (“Sure, that party’s a kegger, but I won’t be drinking, just socializing.” “OK, maybe just one.” “Maybe I’ll just get a little buzzed.”)

You see how it works. Few of us are so strong in our beliefs that we can maintain our standards in a low-profile way when the entire world around us is assailing them.

That’s why fear of embarrassment — fear of being exposed as a hypocrite — is a good thing. To be sure, it’s not the main reason to do the right thing. But realistically, it can be a valuable supplement for us weak, sinful folk. In testifying to the truth before others, we not only help them, we help ourselves.

But as I say, the most important point is helping others. And when we do, a funny thing sometimes happens.

You find, in doing the lonely duty of speaking out for what’s right, that a few other people join you — often people who were thinking the same thing, but just didn’t say it much, usually for the same reasons you hadn’t said it. Then a few more people, and a few more. And before it’s all done, they’ve added up to a decent number.

That, in microcosm, is how good societies are built. And who knows, maybe that’s how ours will be rebuilt.