system
Given the following post, respond as if you're commenting on Reddit:
human
Hey thermodynamics experts, why do stringy things tangle?

Whenever I try to reason this out, I always come back to thinking that in the process of knotting or tangling a string (or headphones cord, or whatever), the number of possible configurations is being constrained, thus reducing the overall entropy of the system, which is illogical, given that things *always* tangle. Also, something something partition function. 


What is actually going on?

I am looking for a thermodynamic or statistical explanation - not something relating to jones polynomials or persistence lengths. 

I'm looking forward to a fun discussion! Thanks.
gpt
Actually, it's that there are very few ways where you can be untangled.

If you have two strings that start parallel and are in a confined space, you can only really call them untangled if they remain in that initial state or a state very similar to it (a low chance, as this is only a few states of many), or end up being located far enough from each other that they can't tangle with each other whatever they do (also a low chance in a confined space, depending on how small the space is). For any other configuration - twists, loops, knots, whatever you want - there are many more possible choices.

For example, you can add many more combinations to the initial parallel strings just by twisting them together, dependent on where the twists are, how many twists there are, and so on. Add more strings, and the amount of combinations where *all* of them stay untangled gets very low indeed!