Thursday, 3 May 2012

Zeno's paradox. And the idea of infinity.

I have just finished the book 'The Fault in Our Stars', by John Green. It was a birthday present from E, and it was genuinely the most beautiful and sad story I have ever read. I'd highly recommend it.
It is a magically written love story between two teenagers with cancer. I finished it in the exam room, and so very nearly cried.
There are elements of the novel that have caused me to think deeply (=brain-hurtingly deep). While the protagonists' aim is to live and to love, there are questions they try to find answers for, questions I have asked before.

The very idea of infinity has always baffled me, and I was lucky enough that it was touched on so though-provocatively in the novel.
When Hazel is asking her favourite author for answers and what happens after the novel ends so suddenly. He tells her about Zeno/Xeno 's paradox.
Imagine you are in a race with a tortoise. The tortoise had a ten-yard head start. In the time it takes to run the ten-yard, the tortoise moves a further one yard. And in the time it takes you to cover that distance, the tortoise will have moved a little farther, and so on forever.
This theorem shows that it is impossible to over take the tortoise, bot only decrease its lead.
We all know it would be easy to overtake the tortoise, however the paradox shows you clearly could not.
As I understand it, the lead the tortoise had will infinitely decrease, but never disappear, because not only are there an infinite amount of numbers, there are infinite amount of numbers between any two numbers.
The explanation to solve this paradox was by Cantor, and on the surface it looks quite simple; some infinities are bigger than other infinities.
There may be an infinite amount of numbers between 0 and 1, but even more between 0 and 2.
So.... I assume you can overtake the tortoise because although the tortoise moves infinitely, you are still faster than the tortoise, therefore your 'infinite moving' (for want of a better term) is bigger/faster in this context.

....
Okay... so that was what I wrote in my revision while everyone was doing their exam :s.... my French paper was only 35 minutes while everyone else's was an hour and a half.
A little on infinity.

In the story Hazel wants to find out what happens after the story. And the impression I get it is that the author is saying that within his story there are infinite amount of moments, even if the story does not go on infinitely...
... and it may seem weird for a love story to talk about infinity. 'Some infinities are longer than other infinities', for me, was the main message in the book.

I'm sorry I sound so vague, I do not want to ruin the story in case someone wants to read it, but haven't.

Byebye for now... sorry for delayed post.

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