I have always had a sneaking suspicion that many people attracted to philosophizing like making up outlandish scenarios; testing theories is just a subtext for creating extraordinary yarns.
Above all others, epistemologists (people who study what knowledge is) are attracted to this seminar room fantasising. The traditional definition of knowledge was "justified true belief". The major problem is that such knowledge can be undermined by sceptical scenarios.
A favourite example of mine involves a girl, let's call her Lavender, who visits a zoo. She thinks she sees a zebra in a cage, it has black and white stripes, four legs and looks like all the zebras she has ever seen. A strange old wizened philosophy professor sidles up to Lavender and asks her what she knows about the thing in the cage. Lavender says "I know that's a zebra." The epistemologist (for that is his speciality) cackles and says "do you, I wager it's a cunningly disguised mule." The problem thus becomes, could Lavender really have the justified true belief in the first instance? For the epistemologist is right, because he himself has painted the mule to fool poor unsuspecting zoogoers and plunge them in to sceptical doubt and also make a bit of money by duping them.
If you take the moral from such considerations what we say we know thus becomes justified belief, but surely we want our justified beliefs to be true? It may well be the case that they are not and so our ability to know what is true in the world has been rocked. Are philosophers having fun or are these sceptical examples a serious way of spending one's time? I say both are true, because these simple examples are ways of dramatising problems we face in making headway in philosophy, but it seems clear to me that such examples are really invented to have a good laugh and what's bad about that?