Here is the story of how I discovered that if you believe in psychic dogs, you must be barking.
Ok, I’ve got a bunch of dogs that bark. Now these dogs aren’t just any dogs, oh no, they’re pretty clever. So, I’ve got a dog (rex) that barks at cats, and a dog (gnasher) that barks at fish, and a dog (fido) that barks at black things, a dog (pig) that barks at white things and some others. But am I happy? No. I want more!
One day, I start playing with a mirror. Most of the dogs look in the mirror and aren’t even remotely interested, but my dog that barks at black things (fido) happens to be black, so when he looks in a mirror, he goes off on one. Some of the other dogs bark at themselves in the mirror as well.
Unfortunately, my mirror is one of those full length ones on the front of a wardrobe, so whenever I want to play with the mirror and the dogs I have to carry the whole wardrobe downstairs (the dogs aren’t allowed upstairs).
So, I think for sometime, and I come up with a plan. I spend months training an amazing psychic dog (meg), which barks if it sees a dog that will bark at itself. This makes it a bit easier, as I don’t need to cart the wardrobe around anymore, meg barks at fido, but not at gnasher, so I can take meg around with me instead of going to all that furniture movement effort.
One day, just for fun, I retrain Meg to bark at the opposite of what she used to bark at. This is fairly easy - she’s pretty intelligent. Now, she barks at dogs that won’t bark at themselves in a mirror. She barks at gnasher now but not at fido anymore.
First published on everything2 (hence the linking style) under the name delfick, with the title “Halting Dog Problem”