Somewhere in your kitchen there is a glass, and you trust it. You washed it, you shelved it, and if I dropped one bead of ink into it right now, you would never drink from it again. Not after a rinse. Not after ten rinses. One drop, and the glass is ruined in a place no sponge can reach. Hold that feeling. This episode is about the people who turned that feeling into law, and about the one room in the world where the feeling was finally told no. In 1986, in a laboratory at the University of Pennsylvania, a researcher named Paul Rozin dipped a dead cockroach into a glass of apple juice. The roach was sterilized. The subjects watched the sterilizing. They knew, as a matter of certified fact, that the juice was clean. Nobody drank it. In another test, people labeled a bottle of plain sugar with the word poison in their own handwriting, and then flinched at their own label. Nothing touched the sugar except a word. The word was enough.

Somewhere ahead of you, on a day no calendar has marked yet, someone you love is going to say a final sentence, and you may be the one who hears it. You will lean in. You will carry what they said for the rest of your life. And you will believe it, because nearly everything in you insists that a person at the end of everything has no reason left to lie. The law believes it too. There is a maxim behind that faith, old enough to arrive in Latin: nemo moriturus praesumitur mentiri. No one about to die is presumed to lie. Out of that presumption the courts built one of the strangest doors in the law of evidence, the dying declaration. Hearsay, the secondhand report of what somebody said outside the courtroom, is generally barred at trial. The words of the dying walk through.

At two in the morning, somewhere in this country, a college student is hitting submit on an essay she wrote herself. Every word is hers. By breakfast, a piece of software will hand her professor a percentage saying a machine wrote it. No hearing, no cross-examination, no appeal. Just the number, and the number is confident, and confidence is the whole product. I have spent the past year writing a book about that number. It is called Swimming the Author. It is out now, in paperback and on Kindle, and the title comes from the oldest confidence machine on record. In the seventeenth century, when a woman in England was accused of witchcraft, one way to test her was water. They bound her, thumbs to toe, and lowered her into a pond. King James himself supplied the theory: the water, being pure, shall refuse to receive the guilty in her bosom. So if she floated, the water had rejected her, and she hanged. If she sank, she was innocent, and she drowned proving it. The pond could only convict. That is the machine. Everything since has been a redesign.