Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

I don't understand this example. Are you claiming the laws of thermodynamics only work with a very high probability?


Yes, the second law of thermodynamics is a statistical law. It is physically possible that all the particles in an ideal gas container will be moving east all at the same time, for example (it doesn't break any law of mechanics), or that a temperature fluctuation will spontaneously appear in a material in thermal equilibrium. It's just that the probability for such spontaneous entropy decreases happening is astronomically small.


The second law of thermodynamics is intrinsically a statistical law.


I'm not a physicist and I probably could have phrased that a little better. The example of a bowl of soup randomly and unevenly changing temperature implies to me that the physical system behaves randomly which I do not believe it does.


Entropy can decrease, just with vanishingly small probability: https://en.wikipedia.org/wiki/Fluctuation_theorem


You don't have a detailed knowledge about the state of every molecule in the bowl soup and its environment, so you have to rely on statistical mechanics. And the current macroscopic state that you observe could correspond to a particular microscopical state that evolves in surprising ways. But the probability is so low that it just doesn't happen.

To make things worse, quantum mechanics is intrinsically random (at least as far as we know) and having a detailed knowledge of the state of the system allowing for certain prediction of its evolution is impossible in principle (and not just in practice).




Consider applying for YC's Fall 2026 batch! Applications are open till July 27.

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: