Long ago Google unofficially abandoned the Do No Evil mantra and replaced it with, no kidding, an “evil scale.” Sometimes you have to chose between the lesser of two weevils, as Patrick O’Brian would say. And frankly, just staying this side of decent is enough for most companies.

So when Twitter CEO Evan Williams said earlier today that one of Twitter’s operating principles was to “be a force for good” I cringed a little.

One of the most important lessons I’ve learned in business, and am still learning, is to never trust anyone who says “you can trust me.” That’s a big red flag that they’re planning something really messed up in the near future. And likewise, a company shouldn’t be out there saying “don’t be evil” or “be a force for good.”

First because it’s basically impossible to balance a profit motive with a goodness motive. And in fact the nice thing about capitalism is that everyone acting in their own self interest tends to be good for everyone else, too, if appropriate government forces are put in place to stop monopolies, pollution, etc. Being a socialist is a great way to get laid in college but it’s no way to run a society.

And second because when people, or governments, or companies start talking about being a force for good, there’s a good chance that a serious amount of self righteousness is brewing behind the scenes. Everyone who fights a war thinks they have God on their side. And some of the most atrocious moments in history were done in the name of good.

What I’d like best is if Twitter just focuses on keeping the lights on, and adds competitive features that keep Google, Facebook and others on their toes. Let others use Twitter to do good things. Twitter should stay goodness-neutral and self righteous free.

Or alternatively try to be a force for good. But just do it, don’t talk about it.