I was having a conversation with my
girlfriend, when her dog came in and
wagged its tail. "You know," she said, "
dogs only wag their tail when other creatures are present."
"Oh, really?" I replied, "how do you know that?"
She said she read it somewhere. So I proceeded to explain that according to the Heisenberg Uncertainty Principle, that would be impossible to know. If there are no creatures (i.e. also no humans around to see), how can we know the dog isn't wagging its tail?
So you can film the dog, without humans there. Okay, so now we know that dogs wag their tails around other creatures, but not when they are being filmed.
What if they don't know they are being filmed?
Dogs always know they are being filmed. At least, so it would appear from this test.