Originally Posted by
LFJ
The question to ask is whether or not something is likely to be true. If you say you have a T-Rex in your backyard, it's not likely to be true because no T-Rex has ever been found living.
However, if you say you have a dog in your backyard, I'd generally be inclined to believe you unless there is some reason for you to be lying about it. I could also go investigate and discover things like dog food in your house, dog turds in the grass, etc., which would lead to a reasonable belief that you in fact own a dog, even without having ever seen it.