Tuesday, 16 September 2014

What is the definition of entropy?

Having recently blogged on the subject:


I feel that it would be helpful for readers to have a clearer definition of entropy.

Luckily, one already exists, in Three Men in a Boat by Jerome K Jerome:

I do not wish to be insulting, but I firmly believe that if you took an average tow-line, and stretched it out straight across the middle of a field, and then turned your back on it for thirty seconds, that, when you looked round again, you would find that it had got itself altogether in a heap in the middle of the field, and had twisted itself up, and tied itself into knots, and lost its two ends, and become all loops; and it would take you a good half-hour, sitting down there on the grass and swearing all the while, to disentangle it again.
That is my opinion of tow-lines in general.  Of course, there may be honourable exceptions; I do not say that there are not.  There may be tow-lines that are a credit to their profession—conscientious, respectable tow-lines—tow-lines that do not imagine they are crochet-work, and try to knit themselves up into antimacassars the instant they are left to themselves.  I say there may be such tow-lines; I sincerely hope there are.  But I have not met with them.
This tow-line I had taken in myself just before we had got to the lock.  I would not let Harris touch it, because he is careless.  I had looped it round slowly and cautiously, and tied it up in the middle, and folded it in two, and laid it down gently at the bottom of the boat.  Harris had lifted it up scientifically, and had put it into George’s hand.  George had taken it firmly, and held it away from him, and had begun to unravel it as if he were taking the swaddling clothes off a new-born infant; and, before he had unwound a dozen yards, the thing was more like a badly-made door-mat than anything else.
A modern equivalent can be observed with the wires attached to those little earphone things that you use for listening to audio devices such as small radios, mobile phones, iPods and the like.