This illusion was discovered by University of California psychologist Diana Deutsch. Listen first with the left and right channels in balance, then isolate each ear. Though the pattern in each channel jumps around in pitch, when they’re combined we tend to hear two smooth scales. Why?

“It is as though the sounds gravitate towards neighbours, where ‘neighbourhood’ is defined not by the physical proximity of the causative events, but by adjacent places on the pitch spectrum,” writes philosopher Roger Scruton. “Yet the sequences as heard are played into neither ear, and represent no causally unified process in the physical world. The auditory Gestalt is not merely incongruous with the physical events that produce it. It is organized according to principles that are intrinsic to the world of sounds, and which would be operative even if there were no physical events that could be identified as the causes of the individual sounds.”

(Roger Scruton, “Thoughts on Rhythm,” in Kathleen Stock, ed., Philosophers on Music, 2007.)

Reader Colin Brown sent this in: In the Harvard Libraries in 2008 he checked out a history of Tillamook County, Oregon, and of cheesemaking in particular, issued in the 1930s by the Oregon Journal. There were two volumes: Volume One was a book titled Cheese Cheddar, and in place of Volume Two he found a note taped to the inside cover:

Note for the Cataloguer:

Vol. II of this work was a two pound piece of Cheddar Cheese. The Librarian can attest to its excellent quality and to the fact that it no longer exists. Sic transit gloria caseii.

A.C.R.

Dec. 31, 1933

“The book was noted as a personal gift of Charles H. Taylor, Jr., but it was unclear whose initials those were on the added sheet,” Colin writes. “When I checked the book out in 2008, it had only been checked out one other time since its donation (in 1944).”

He adds, “I informed the library and they have archived it in their protected section of the Widener Depository for unusual addenda or marginal notes.”

(Thanks, Colin.)

A British officer in the 44th regiment, who had occasion, when in Paris, to pass one of the bridges across the Seine, had his boots, which had been previously well polished, dirtied by a poodle Dog rubbing against them. He in consequence went to a man who was stationed on the bridge, and had them cleaned. The same circumstance having occurred more than once, his curiosity was excited, and he watched the Dog. He saw him roll himself in the mud of the river, and then watch for a person with well polished boots, against which he contrived to rub himself. Finding that the shoeblack was the owner of the Dog, he taxed him with the artifice; and, after a little hesitation, he confessed that he had taught the Dog the trick in order to procure customers for himself. The officer being much struck with the Dog’s sagacity, purchased him at a high price, and brought him to England. He kept him tied up in London for some time, and then released him. The dog remained with him a day or two, and then made his escape. A fortnight afterwards he was found with his former master, pursuing his old trade on the bridge.

— Samuel Griswold Goodrich, Tales of Animals, 1835

A conundrum by Oxford philosopher Derek Parfit:

In several years, a young Russian will inherit vast estates. Because he has socialist ideals, he intends, now, to give the land to the peasants. But he knows that in time his ideals may fade. To guard against this possibility, he does two things. He first signs a legal document, which will automatically give away the land, and which can be revoked only with his wife’s consent. He then says to his wife, ‘Promise me that, if I ever change my mind, and ask you to revoke this document, you will not consent.’ He adds, ‘I regard my ideals as essential to me. If I lose these ideals, I want you to think that I cease to exist. I want you to regard your husband then, not as me, the man who asks for this promise, but only as his corrupted later self. Promise me that you will not do what he asks.’

She agrees. In time the Russian’s ideals fade, and when he inherits the land he asks his wife to revoke the document, declaring that he releases her from her earlier commitment. What is her obligation here? She had made her promise to her earlier husband, but is that a different person from the man before her now? In her view, the man to whom she made her promise no longer exists, and so cannot release her from her obligation. Is this right? If a person is a succession of earlier and later selves, does a promise attach to a person or to a self?

(Derek Parfit, Reasons and Persons, 1984. See The Ulysses Contract.)

Partially paralyzed in the Boer War, British infantry officer Hugh Trenchard traveled to Switzerland to recuperate and took up tobogganing out of boredom. Because he couldn’t brake properly, he traveled dangerously fast, and one day the toboggan leapt over the bank and parted company with him in midair. “His body hit the side of the hill two or three times before coming to rest in a snowdrift nearly thirty feet below”:

When he came to his head was throbbing violently. Solicitious hands raised him. He pushed them aside in a sudden fury of excitement and happiness. He could walk again unaided. Whatever other damage he might have done himself as he bounced down the hill-side like a rubber ball, he had recovered the use of his legs. Apart from a dull pain near the base of his spine he felt no aftereffects. Something must have clicked back into place; he had cured himself by violence.

Before the accident he could walk only with sticks; now he threw them away. For good measure, he won the freshman and novices’ tobogganing cups for 1901. Biographer Andrew Boyle writes, “It was a singular achievement for a man with no previous experience, and for one regarded as a virtual cripple until the week before the event.”

Trenchard went on to play a central role in establishing the Royal Air Force.

(From Andrew Boyle, Trenchard, 1962.)

Half sleepless night again — an entirely disgusting dream, about men using flesh and bones, hands of children especially, for fuel — being out of wood and coals. I took a piece to put on someones fire, and found it the side of an animals face, with the jaw and teeth in it.

— John Ruskin, Brantwood Diary, Oct. 29, 1877

I had a dream last night. An amputated head had been stuck on to a man’s trunk, making him look like a drunken actor. The head began to talk. I was terrified and knocked over my folding screen in trying to push a Russian in front of me against the furious creature’s onslaught.

— August Strindberg, Inferno, 1897

The nightmares returned — one terrible one in February 1896 about a tramp, seen holding over a well ‘washing, but with a kind of amused tenderness, an object that I thought was a rabbit, but I presently saw that it was a small deformed hairy child, with a curious lower jaw, very shallow: over the face it had a kind of horny carapace … made of some material resembling pottery. I was disgusted at this but went on, and it grew dark: I heard behind me an odd sound, and turning round saw this horrible creature only a foot or two high, walking complacently after me, with its limbs involved in ugly and shapeless clothes, made, it seemed to me, of oakum, or some more distressing material. The horror of it exceeded all belief.’

— A.C. Benson, quoted in David Newsome, On the Edge of Paradise, 1980