You can get into a habit of thought in which you enjoy making fun of all those other people who don't see things as clearly as you do. We have to guard carefully against it.

Both Barnum and H. L. Mencken are said to have made the depressing observation that no one ever lost money by underestimating the intelligence of the American public. The remark has worldwide application. But the lack is not in intelligence, which is in plentiful supply; rather, the scarce commodity is systematic training in critical thinking.

deluded or not, supporters of superstition and pseudoscience are human beings with real feelings, who, like the skeptics, 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.

Those who make uncritical observations or fraudulent claims lead us into error and deflect us from the major human goal of understanding how the world works. It is for this reason that playing fast and loose with the truth is a very serious matter.

Why do we put up with it? Do we like to be criticized? No, no scientist enjoys it. Every scientist feels a proprietary affection for his or her ideas and findings. Even so, you don’t reply to critics, Wait a minute; this is a really good idea; I’m very fond of it; it’s done you no harm; please leave it alone. Instead, the hard but just rule is that if the ideas don’t work, you must throw them away.

The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what's true.

When I wake up I go through an abbreviated process of mourning all over again. Plainly, there’s something within me that’s ready to believe in life after death. And it’s not the least bit interested in whether there’s any sober evidence for it.

Why does Alexander the Great never tell us about the exact location of his tomb, Fermat about his Last Theorem, John Wilkes Booth about the Lincoln assassination conspiracy, Hermann Göring about the Reichstag fire? Why don’t Sophocles, Democritus, and Aristarchus dictate their lost books?

Another of Mack’s patients says that the aliens have been taking eggs from her since she was sexually mature, and that her reproductive system baffles her gynecologist. Is it baffling enough to write the case up and submit a research paper to The New England Journal of Medicine? Apparently it’s not that baffling.