The Character of Physical Law

The one thing in the whole of science that I have found most captivating and enigmatic, pretty much ever since I first came across it (probably sometime in my early teens), is the Second Law of Thermodynamics. I still find it quite incredible how fundamental and deep-seated the idea seems to be: from car engines and refrigerators to cells and living organisms and entire human societies, the working of everything around us is a manifestation of this law, which underpins the phenomenon of irreversibility and the nature of time itself. In my school days, the fascination was a bit more prosaic: one of the reasons being simply that our textbooks contained so many different 'statements' of the law. For a naïve schoolchild brought up under an education system which essentially encouraged one to cram oneself with immutable scientific 'laws', to be regurgitated verbatim during exams, this was quite a novelty. The fact that the same principle could be expressed in so many entirely different ways meant it must be somehow special, and this was one of the things that first tickled my scientific antennae. My favourite statement of the law, however, has to be one that I first heard just a couple of days ago, at a fascinating lecture by a famous physicist:

"If you eat, you have to go to the toilet".

I wish I'd thought of that when writing my physics exams...