Friday, October 31, 2008

Exact Numbers

Recently I have been counting steps as I walk. I pick particular short stretches along frequently traveled routes and count each time I walk them. The numbers vary quite a bit. I can't say, for example, that a stretch of sidewalk is 54 steps long, but I could give a pretty good guess of the mean at 54 and the shape of the distribution.

It's natural to believe that the exact number of steps does not exist, because once you walk it, it vanishes. Each time you try to count it, you will get a different number. The distribution eventually takes a characteristic shape, but each time you walk it, the outcome is unpredictable.

Now another counting problem. Count the number of ants in New Brunswick. You can't actually go and find every single ant. Even if a team of 100 people committed a year to it they wouldn't find every single ant. You'd have to get some kind of an estimate. And it wouldn't be exactly right, and every time you did it, you'd get a slightly different estimate.

Now the question is, does the number of ants exist? First, a slightly less weird question: is there any way to observe the exact number of ants directly? My inclination to this question is no, simply because I haven't thought of a way to do so. Then a slightly harder question: is there a way to observe the exact number of ants indirectly? Another way to put it, is the number of ants divisible by three, and how would we ever know? The question this is getting at is, is there any way in which whether the number of ants is divisible by three will affect our experience in a way that is observable to us? This is the really careful way of asking, is the world in which the number of ants exists any different than the world in which that number does not exist? Which is yet again a really careful way of asking, does the number of ants exist? Again my inclination is no, but only because I haven't thought of a way to make it exist.

Anyone who thinks we live in a deterministic world hasn't looked around them recently enough.

Tuesday, October 21, 2008

Desk Writing

SEC-205 has some of the best writing on the desks. Here is a sample:

Hello person sitting at this desk
Hello, o you fr
Hello to both of you.
Hello you three.
Goodbye
You say goodbye and I say hello
ppl, go see Forgetting Sarah Morgan...
Ridiculous
Yeah I wanna see that (and Ironman)
I like bunnies. <-- bunnies? No one likes bunnies!
Hello you four. Though I will be parting my seat forever, I wanted to let you know your messages were entertaining. I shall take your advice and see the movie. Farewell fellow desk writers.

It's not goodbye, it's _I'll see you later
Farewell to you all !! :)

Monday, October 20, 2008

Relativistic Asteroids

I have long been bothered by the lack of relativity in the arcade game asteroids. This problem has been addressed! See Relativistic Asteroids.

By the way, does anyone know a portable way to embed an applet in xhtml 1.1?