It seems to me what is called for is an exquisite balance between two conflicting needs: the most skeptical scrutiny of all hypotheses that are served up to us and at the same time a great openness to new ideas. Obviously those two modes of thought are in some tension. But if you are able to exercise only one of these modes, whichever one it is, you’re in deep trouble.

If you are only skeptical, then no new ideas make it through to you. You never learn anything new. You become a crotchety old person convinced that nonsense is ruling the world. (There is, of course, much data to support you.) But every now and then, maybe once in a hundred cases, a new idea turns out to be on the mark, valid and wonderful. If you are too much in the habit of being skeptical about everything, you are going to miss or resent it, and either way you will be standing in the way of understanding and progress.

On the other hand, if you are open to the point of gullibility and have not an ounce of skeptical sense in you, then you cannot distinguish the useful as from the worthless ones.

If you’re only sceptical, then no new ideas make it through to you. You never learn anything. You become a crochety misanthrope convinced that nonsense is ruling the world. (There is, of course, much data to support you.) Since major discoveries in the borderlines of science are rare, experience will tend to confirm your grumpiness. But every now and then a new idea turns out to be on the mark, valid and wonderful. If you’re too resolutely and uncompromisingly sceptical, you’re going to miss (or resent) the transforming discoveries in science, and either way you will be obstructing understanding and progress. Mere scepticism is not enough.

The business of scepticism is to be dangerous. Scepticism challenges established institutions. If we teach everybody, including, say, high school students, habits of sceptical thought, they will probably not restrict their scepticism to UFOs, aspirin commercials and 35,000-year-old channellees. Maybe they’ll start asking awkward questions about economic, or social, or political, or religious institutions. Perhaps they’ll challenge the opinions of those in power. Then where would we be?

At the heart of science is an essential balance between two seemingly contradictory attitudes — an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense.

Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.

If we offer too much silent assent about mysticism and superstition - even when it seems to be doing a little good - we abet a general climate in which scepticism is considered impolite, science tiresome, and rigorous thinking somehow stuffy and inappropriate. Figuring out a prudent balance takes wisdom.

Scepticism is the chastity of the intellect, and it is shameful to surrender it too soon or to the first comer: there is nobility in preserving it coolly and proudly through long youth, until at last, in the ripeness of instinct and discretion, it can be safely exchanged for fidelity and happiness.

Great intellects are skeptical.

I am suspicious of my existing ideas, my conscious thoughts and convictions. They are what I need to get beyond, into ignorance and after that, with luck, discovery.

We wish to find the truth, no matter where it lies. But to find the truth we need imagination and skepticism both. We will not be afraid to speculate, but we will be careful to distinguish speculation from fact.

Scepticism is the first step towards truth.

In the way that scepticism is sometimes applied to issues of public concern, there is a tendency to belittle, to condescend, to ignore the fact that, deluded or not, supporters of superstition and pseudoscience are human beings with real feelings, who, like the sceptics, are trying to figure out how the world works and what our role in it might be. Their motives are in many cases consonant with science. If their culture has not given them all the tools they need to pursue this great quest, let us temper our criticism with kindness. None of us comes fully equipped.

Both scepticism and wonder are skills that need honing and practice. Their harmonious marriage within the mind of every schoolchild ought to be a principal goal of public education. I’d love to see such a domestic felicity portrayed in the media, television especially: a community of people really working the mix - full of wonder, generously open to every notion, dismissing nothing except for good reason, but at the same time, and as second nature, demanding stringent standards of evidence; and these standards applied with at least as much rigour to what they hold dear as to what they are tempted to reject with impunity.

The skeptic does not mean him who doubts, but him who investigates or researches, as opposed to him who asserts and thinks that he has found.