Complexity in physiology and in society

I was thinking about the amount of complexity in human physiology compared to the amount in social affairs.

The amount of complexity in physiology is very large, but it is arguably bounded.    There are a certain number of molecules that interact in certain ways.   These numbers are both large, but in general, they don't change or grow arbitrarily.   That makes the problem huge, but within reason, bounded.   Hence, it is imaginable to get a good understanding by putting out an immense amount of work and creativity.

This isn't true for social situations.   In society, the actors are changing all the time and the ways they can and do interact change in unpredictable ways.    I would not call these changing patterns random, but the situations in which they occur are so complex and subject to change that it seems like an almost impossible problem to gain a complete understanding.

It's a bit like the difference between Newton's laws of motion (F  = ma), where the basic law is simple, but the effects are vastly complicated, and Boltzmann's statistical mechanics, where he didn't even begin to try to try to predict the actions of individual molecules, but with the difference that the individuals involved having a much larger range of potential actions.

We do try to predict social trends, but with uncertain success.   It still seems to me that it should be possible to get enough of a clue to be able to do some degree of meaningful modeling, but modeling that should be used with a lot of care and checking to see the effect of any changes.