Chapter 16 EXTRA: More about the Schrödinger Cat Paradox

...... "This paradox has been around for about three quarters of a century," said Dr. Ralph, "and it's still going strong. He sketched the two slit experiment--something the boys were very familiar with by now.
...... Dr. Ralph exchanged a few comments with his class, then erased the board and drew something else: a box with hole in it and a diagonal line inside the box near the hole.
...... Dr. Ralph pointed to the line. "This is a half-silvered mirror. An electron goes through the hole and hits the mirror. Now, just like the two slit experiment, the electron in some sense both goes through the mirror and also is reflected off the mirror."
...... "You say in some sense a lot," said Kip.
...... "I do." Dr. Ralph chuckled. "But I don't guarantee it isn't nonsense." He turned back to his drawn diagram. "Okay," he went on. "Let's say that if the electron goes through the mirror, it hits a switch that turns on a high-powered laser." He drew a laser, its beam, and a bottle of milk. "And the beam goes into the milk and turns it sour."
...... "The Schrödinger Milk paradox!" a kid called out.

[Schrödinger Milk Paradox]
...... Dr. Ralph chuckled, then turned to the class. "So to us quantum physicists outside the box, we'd have to say that since both paths of the electron are possible, in the box"--he glanced at Kip--"in some sense both cases exist: a bottle of fresh milk, or spoiled milk." He drew an open door on the side of the box. "So if, a week later, we take out the bottle, the milk inside would have the dual reality of being sour or not sour--and the milk wouldn't make up its mind until we opened the bottle and tasted it."
...... "That's ridiculous," said Paul. "Isn't it?"
...... "Sure it is," said Dr. Ralph with a smile. "The date on the milk bottle is for two months ago. I don't have to open it. I know it's spoiled."
...... "You know what I meant."
...... Dr. Ralph nodded. "But instead of putting a bottle of milk in the box"--He lifted up Paradox, set him on the table, and dropped the cardboard box over him.--"let's say an evil scientist steals Paradox and puts him in the box instead.
...... I'm afraid to open the box. For until I do, Paradox is both alive and dead. But when I open it, there's a fifty percent chance my opening the box will force my cat to be dead." Paradox meowed, loudly. "Of course the evil scientist's box doesn't let any information in or out--especially meows." He turned back to Paul. "Yeah. It probably is ridiculous."
...... "I'm serious," said Paul. "Are we supposed to, like, believe this?"
...... "Until a reason is found why big things--like cats--don't have quantum effects like electrons, the Schrödinger cat paradox is just that--a paradox."
...... "Do you believe it, sir?" said another of the boys.
...... "I...I don't exactly know. Nature might be trying to tell us something about reality--but we're too dumb to understand what." Dr. Ralph turned and lifted the box. Paradox jumped back to the floor. "Paradox," said Dr. Ralph in a mock-serious voice. "You're alive!"
...... Most of the kids laughed, but Kip merely smiled.
...... "And what if, instead of a cat, a human was in the box?" Dr. Ralph went on. "He'd certainly know if he were dead or not. Or what if a whole planet were in the box, or a galaxy? Is there a different reality inside and outside of the box?" He shrugged. "It's weird. That's why it's called a paradox." Then, with an air of finality, Dr. Ralph pushed a button and the blackboards went blank.

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