Tuesday, April 14, 2009

On Causality

You see, when you ask why something happens, how does a person answer why something happens?

For example, Aunt Minnie is in the hospital. Why? Because she went out on the ice and slipped and broke her hip. That satisfies people. But it wouldn't satisfy someone who came from another planet and knew nothing about things...

When you explain a why, you have to be in some framework that you've allowed something to be true. Otherwise you're perpetually asking why... You go deeper and deeper in various directions.

Why did she slip on the ice? Well, ice is slippery. Everybody knows that-no problem. But you ask why the ice is slippery... And then you're involved with something, because there aren't many things slippery as ice... A solid that's so slippery?

Because it is in the case of ice that when you stand on it, they say, momentarily the pressure melts the ice a little bit so that you've got an instantaneous water surface on which you're slipping. Why on ice and not on other things? Because water expands when it freezes. So the pressure tries to undo the expansion and melts it...

I'm not answering your question, but I'm telling you how difficult a why question is. You have to know what it is permitted to understand... and what it is you're not.

You'll notice in this example that the more I ask why, it gets interesting after a while. That's my idea, that the deeper a thing is, the more interesting...

Του Richard Feynman, από τη βιογραφία του James Gleick, Genius.