In any American political campaign, credulity is rampant when skepticism is what's called for.

Henri Poincaré remarked: "We know how cruel the truth often is and we wonder whether delusion is not more consoling." Thus religion. But I don't think consolation is the only reason credulity is rampant in 21st century America. Skepticism challenges established institutions. If we school everybody in the habit of being skeptical, they might not restrict their skepticism to, let's say, deodorant advertising claims or the existence of UFOs. They might start asking very awkward questions about our economic, or social, or political, or religious institutions. Then where will we be?

The plain truth is that skepticism is dangerous to the status quo. That, I think, is exactly its function. It is the job of skepticism to be dangerous. And that's why there is a great reluctance to teach it in public schools. That's why you don't find a general fluency in skepticism in the entertainment (that includes the news) media. On the other hand, how can we negotiate a perilous future if we don't have the most basic intellectual tool to ask searching questions of those trying to solicit our votes and control how our tax dollars are spent?

I think this is a useful time to reflect on the sort of national trouble that could have been avoided were skepticism more generally employed in American society. The Vietnam fiasco and the Iran-Contra scandal are such obvious examples they don't need to be rehashed. The Bush Administration's resistance to finding solutions through diplomacy and its continuing passion for blowing up foreign people under the pretense of making us safe and secure at home is another such issue. Obviously, there is enough nonsense promulgated by both political parties that the habit of evenhanded skepticism should be declared a national priority and an essential tool for our survival.

I want to say a little more about the burden of skepticism.

You can get into a habit of making fun of those other people who don't see things as passionately as you do. We have to guard carefully against the habit of labeling them and dismissing their ideas out of hand. What is called for in a nation like ours is a balance between two conflicting needs: the most skeptical scrutiny of the hypotheses that are served up to us (especially by religious figures and politicians), and at the same time, maintaining an openness to new ideas, which may involve abandoning old ones. Obviously those two modes of thought are in some tension. But if you are able to exercise only one of them, whichever one it is you're in deep trouble.

If you are only skeptical then no new ideas can make it through to you. You never learn anything. You become a crotchety old curmudgeon convinced that nonsense is ruling the world (and there is a great deal of data to support you).

Every now and then a new idea turns out to be right on the mark. If you are in the habit of being overly skeptical about everything, you are going to miss out on it or resent it and either way you will be standing in the way of progress for everyone.

On the other hand, if you are open to the point of gullibility and have no skeptical sense then you cannot distinguish the useful from the worthless, the exaggeration from the reasonable, the lie from the truth. If all ideas have equal validity, then no ideas have any validity.

It is a truism that some ideas are better than others. The machinery for distinguishing between them is an essential tool in dealing with our form of government and especially in dealing with our future, if we are to have one at all. And it is precisely the mix of these two modes of thought, skepticism and acceptance, that is central to the success of a nation like ours. The illiterate of the 21st century will not be those who cannot read and write, but those who cannot learn, unlearn and relearn.

(with gratitude to Carl Sagan)