One Night, on a camping trip, Sherlock Holmes wakes up Watson and says, "Look at the stars. What do you deduce?"
Watson thinks for a minute and says, "Well, I see millions of stars, many of which resemble our sun, which most likely have their own planets, which most likely have life-forms like us, so I deduce that there is life on other planets."
And Sherlock says, "No, you idiot, someone's stolen our tent."