Or to put it even more simply: I don't know that there isn't a tiger behind the door to this room. Tigers are not generally known to roam the highways and byways of the Black Country but there might have been an escape from relatively-nearby Dudley Zoo or something; and though the house is locked up, the animal might have squeezed in through a window, being a cat and all. However, my lack of knowledge regarding a tiger behind the door isn't a good enough reason for me to be too scared ever to open the door to leave the room. Yes, there is that zillions-to-one chance that if I open the door I will become lunch for an overgrown tabby cat. However, the odds are rather in my favour that I ought to be able to stride straight through the door, wouldn't you say? After opening it first, of course. Or am I trapped in this room for, if not forever, then at least for the typical lifespan of the average tiger? You know, just in case?
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'