Since writing my previous post on the second law of thermodynamics I’ve been wondering just how seriously to take the premise that human intention has the power to reverse it. Feedback so far has been limited, so I’ve mostly been focusing on other things, but I’ve also done some quick research.
One interesting thing I found from wikipedia was that there seems to be a fair amount of controversy and confusion regarding the definition of entropy. This is in some ways remarkable, given (i) the fact that it is THE key concept around which the second law is generally formulated, and (ii) the second law is taken to be so fundamental in physics. How can we be so sure of a law when we can’t even agree about the definition of the key concept around which it’s formulated?
One aspect of the controversy concerns the idea that entropy is a measure of how disordered a system is. This idea seems to be going out of vogue, at least in the teaching of chemistry in the US, essentially on the grounds that it confuses students and distracts from more precise definitions in the context of real-world, earth-bound chemical processes. But if we really want to make a fundamental law out of the idea that entropy tends to increase, then it seems to me that we need to do better than just “heat tends to flow from a hotter to a colder body”. It doesn’t, not at the scale of stars and galaxies. That’s why, in the words of Roger Penrose, the sun is a “hot spot in a cold sky”, which is basically why life on earth is possible.
In any case I would welcome views on this. Don’t feel the need to be an “expert” in order to comment. Sometimes experts get wrapped up in their own jargon, while “non-expert” views are necessary to reconnect with day-to-day reality. (Expert views are also welcome of course.)