A foray into the real world

When the company of "abstract nonsense" becomes too bewildering, it seems appropriate to return to reality and consider some real-life problems. Well, probably...

So suppose I have two children, and I tell you that the older one is a boy. What is the probability that I have two boys?

1/2 of course. Probability is easy.


Suppose, instead, that I tell you that at least one of my children is a boy. What is the probability that I have two boys?

1/3. Probability is tricky, but still easy.



Just for fun, suppose I told you that my son, Mark, is celebrating his birthday next Tuesday. What is the probability that I have two boys?

1/2. Tuesday is a red herring, surely.



Just for the hell of it, suppose that I tell you that at least one of my children is a boy, and that his birthday is on a Tuesday. What is the probability that I have two boys?

Slightly less than 1/2. Actually, it's 13/27, if I didn't mess up.


Suppose I mumbled, "At least one of my children is a boy, and his birthday is on a @?£$day (...inaudible...)." What is the probability that I have two boys?

Still 13/27.


Finally, suppose I mumbled even more. "At least one of my children is a boy, and he ... (inaudible)..." What is the probability that I have two boys?

Infinitesimally greater than 1/3.


At this point, the classical world just seems plain weird to me. I'm going back to the quantum one.

Slovenian madman

I recently discovered Slovaj Zizek. He's amazing in his biting critique of culture, society and politics, not to mention controversial, but at least, never dumbed down. Certainly you'll have to entertain dangerous thoughts, in order not to see him as a complete basket case.

Among other things, Neils Bohr was a self-styled philosopher, and Zizek reminded me of an interesting anecdote I'd read somewhere sometime ago. A visitor of Bohr was puzzled to see a horseshoe hung in Bohr's home, and asked him why he had displayed an object of superstition in his home. Bohr explained that he was not an idiot, but that he had been told that the horseshoe works... even if you don't believe in it.

Zizek also had a gentle remark about an old movie I'd watched about ten years ago. It's an Italian movie called "La vita e bella" --- Life is beautiful. If you had watched the movie, you'll remember the heart-wrenching scene at the end when Giosue was greeted by the tank that his father Guido had promised him. Guido had created an elaborate game for his son in order to shield him from the realities of the concentration camp they were living in, and ultimately sacrificed his own life in doing so.

Zizek suggested an alternative, and devastatingly sombre double-bluff ending. That Giosue had known all along what Guido was trying to do... and that he was merely playing along so as not to disappoint his father.