During the Vietnam War, hundreds of thousands marched on Washington. A few years ago, Louis Farrakhan organized the Million Man March.

I fantasize about holding National Boycott Stupidity Day and getting the same kind of turnout — throngs of citizens tired of popular culture’s ongoing celebration of idiocy and ignorance as greater virtues than logical analysis and knowledgeable discourse.

I don’t want to blow this out of proportion. I enjoyed Luke Skywalker’s decision to trust the force as much as anyone. But Luke’s decision was trusting his own coordination over that of a computer, not “trusting his instincts” instead of logic to make a decision. Popular culture has it that our brains should defer to our guts, despite conclusive anatomical evidence that guts digest food while brains digest information, and the success of the scientific method demonstrating that facts and logic are superior to instinct.

This week we wrap up our series on decision-makers. So far we’ve shot at lawyers, marks, zealots, and politicians. This week we’ll wrap things up with scientists and card players.

Given science’s inarguable success, you might think scientific decision-making is the way to go in business. There’s a lot to be said for it. Occam’s razor, for example — that among the explanations that account for all known facts you should always prefer the one requiring the fewest assumptions — is smart advice. So is the corollary that there’s always room for doubt, no matter how carefully you’ve tested a theory, because new facts may arise at any time.

But scientists can become as paralyzed as lawyers by the need for yet more data. While they understand that proof is impossible, they’re remarkably adept at envisioning what additional evidence might be gathered to reduce doubt even further.

Good card players avoid this paralysis. Consider the game of bridge, where much of the deck is hidden. While the bidding, the dummy, your own hand, and statistical probability all provide evidence of where the hidden cards lie, your information is limited. Even so, you have to decide how to play the hand.

It’s a good metaphor for the manager’s job — making decisions despite imperfect information, while taking into account every card that’s played (new information) to adjust tactics.

There are those who prefer poker or chess as decision-making metaphors. Let’s not quibble — as metaphors, each illustrates worthwhile principles.

The important point is this: Certainty is impossible, but you have to make decisions anyway. And while many figure uncertainty is the time to listen to your gut, they’re wrong.

Uncertainty demands the use of your brain. When your gastrointestinal tract talks, that just means it’s lunchtime.