“No one ever thinks the cat is real at first.”
He paused, holding a spoonful of sugar in his hand, and studied it for a moment, before adding it to his coffee.
“It was just a thought experiment. A way for Erwin Schroedinger to explain quantum mechanics to his students, and to more than one stubborn professor who didn’t want to concede the universe could be random. You can’t really build a box to keep a cat alive and dead at once. Even if you get past the ethical questions, the animal rights protesters from PETA and the surprising number of furries in academic circles, there’s the sheer cost. This isn’t just a some faraday cage to keep out electromagnetic waves. The Observer in this experiment isn’t some old dude in a white lab coat looking down a microscope, the observer is reality. The only way to create the superstate where two realities exist at once is to stop the rest of the universe interacting with the box. Not one photon, not one quark, not one subatomic particle or wave can interact with that box. Because when it does, then the universe has observed the box.”
He paused for a moment, taking another drink from the mug, savouring the taste and smell of the dark coffee.
“So no, you can’t build it. But eventually, if your world doesn’t destroy itself first through nuclear war or catastrophic climate change, you’ll realise it just might be possible to build the box. Not easy, but possible. And eventually, every experimental physicist starts to wonder. What if you really did build the box. And then, what if you could look inside.”
The traveller smiled.
“And here I am.”
He paused again, and added milk to his coffee, stirring it for a moment and then watching as the dark and light merged into a warm brown.
“So then you realise, if you can do it once, you can do it again, and then there are close to an infinite number of possible combinations and worlds. Every choice, every action, at a sub molecular level, since the beginning of time. Each one represents a possible universe. Granted, most of them are empty. Cold lifeless lumps where the first spark never ignited. And even more where the universe cooled down and died. But there are just as many which look like my own world, each a little different. So when our world started to die, we decided it was time to move. We just have to find the best place to settle.”
He sipped the coffee for the first time.
“This really is the best coffee I’ve ever tasted, and I’ve sampled a lot of worlds.”
“So you want to settle here?”
“Oh no. This world is terrible. I just dropped by to save the coffee beans.”
