This is not a mathematical post. I am not a mathematician or even someone with all that much mathematical education. I am someone who considers my base thought on this matter to fall more in philosophy, but I do have an interest in mathematics which will, I warn you, touch this post a bit. This is a post not about something mathematical, but inspired partly by mathematics. This won't require much knowledge of mathematics, I intend to discuss a topic on a conversational level, and maybe make people think. It differs from a mathematical discussion, because it doesn't require a background with the subject matter, but I'm afraid it is rather abstract making it hard to mentally pinpoint, and of course, fun.
There's something funny about not knowing the answer to something. It's hard to accept not knowing it for a lot of people, or at least annoying. It's difficult, on the other hand to deal with whether or not there IS an answer.
A recent episode of This American Life entitled Contents Unknown unknown answers are confronted. In the intro, they discuss a theory that a recording of Hitler and a psychotherapist is out there, explaining why he wanted to do the things that he did. Ron Rosenbaum and Ira Glass say that it comforts people to think that at least the answer exists, even if we won't see it.
A few years back, when I was realizing my interest in math, I came to a development that frankly excited me. Something called "The Continuum Hypothesis." And equally interesting is how the discussion over whether or not it was true ended. Here's where I need a slight history of mathematics break. If you wish to skip that context, that I feel is important and you might not, go to after the change in font face.
One astounding leap in mathematics, was the notion that you can have two sets with infinite members, and one will be bigger than the other. Here's what they look like. Three infinitely roomed hotels are next to each other. Two are empty, the last is full. The rooms (which happens to be called "Hôtel Naturelles" owned my a man named Hilbert) of the full one are numbered like this "1, 2, 3, 4, 5, 6, 7, 8, 9..."
A customer walks into the full one because, well, the room service is great and cheap, and internet is free, and that's why every room is taken. He sees they are full, but walks in and sees when a room will be available. "Right now, if you like," says the attendant. He then asks the first of infinite customers to move a room down, and have the next guest do the same, and so on, ad infinitum. Thereby leaving the room empty.
Bad news, the terminators are coming by for the best paying job ever, and they tell everyone they have to find a new hotel to sleep in. The hotel next (Hotel Quadrat) to it is empty, and has just as infinitely many rooms, except the numbers are perfect squares "1, 4, 9, 16, 25, 36, 49, 64 ..." The rule here is "If you were in a room, square the room number and move into that room in our neighboring hotel."
The customers fill every one of the rooms in that hotel, leaving all rooms taken. Now the first one is uninhabitable, the second one is full, the third one is empty, when the disgruntled bellhop (who looks a little like Tim Roth) says he's tired of going to room g64² and tells management that he wants every last person out before he divides them all ... by zero. Seeing no other choice, Management sez "get" and closes doors for good, locking the doors, and telling the bellhop there's one left... somewhere down there (which is a lie).
Customers go next door. Hotels One and Two are closed, the Third (Hotel Real) is empty, they all arrive but the room numbers are far less organized. There is actually a room corresponding to every real number. Not in order, which sucks for the delivery guys, but they can deal. Having no clear and easy way to decide on which room to take, the moved guests decide to go to rooms that have their original room numbers. The guy who we started with buy walking into the first hotel has room one, and the guy he moved goes to room two, etc, etc.
The Third hotel now has an infinite number of rooms left. If a new guest walks in, the attendants can say "pick any room that isn't a whole, positive number." And the percentage of rooms taken is exactly 0%. That's right. Zero. Pick a room at random, and you won't get one with a guest in it. It's got infinitely more rooms than the first two hotels did, which, by the way, had the same number of rooms but named their room numbers in a different fashion. If Hotel 3 was full, and the terminators came by for an even BIGGER job, there is no way that the people could get rooms by moving into even both of the other two hotels, there would always be infinitely more, which makes it a bigger infinity.
The question is this: if we consider the one infinity that's smaller, and the other that is bigger, is there an infinity somewhere between? Can there be a set with more members than one, and not of the other? Cantor couldn't figure it out. No one could within his lifetime, or for a really long time after that.
Here's where it gets upsetting. This is no longer an open problem. That usually means I can say "Yea" or "Nay" to the statement "There is an hotel larger than the first two, but smaller than the third." Not this time. The precise reason it is not an open question is because we know that we cannot ever find that answer.
This means, if you actually have to deal with that, assume it's true. Or assume it's false. Then just keep going. But the real problem is, does this mean that neither answer is correct, or just that we can't know? The guy who did half the work finding this stuff out, Kurt Gödel, who himself was responsible for the possibility of answers like this to happen (which earned him from David Foster Wallace the nickname "Dark Prince of Mathematics") himself thought that not only could there be a hotel between those two (despite knowing that he had no reason to believe this) but there are an infinite number of infinities between those two which could be properly ordered in size. Which means he of course thought there was an answer, but we logically cannot know it.
And there I got fascinated, and I also got frustrated. I thought I probably disagreed with Kurt, that there is not an answer at all, like as if it were a paradox, or the question were badly worded (and there are plenty of those.) But the question is worded fine and isn't a paradox even if it is highly and terribly abstract and almost unthinkable. I decided that the answer of which I am only partially convinced is that the unprovable or "independent" statement means that since math only happens in some places to correspond with real things, here it does not, and therefore there is no real truth like there is with the existence of a tape of Hitler, or the contents of a lost letter. Though I am not convinced that there utterly can't be an answer? And why is it that I am comforted by neither possibility?
Unknowing is fine when we think we could even possibly see the answer. Does that tape of Hitler and the psychotherapist exist? We might know, someday, and we'd like to think there's an answer. But that's the only comfort we may ever take, and blind ourselves to the possibility: I am sorry, Ignorabimus! (We Shall Not Know.)
