system
Given the following post, respond as if you're commenting on Reddit:
human
What is the cause of diffusion and osmosis? How does it work?

I know the general gist of how diffusion/osmosis works, I just don't know *why* it works like it works.
gpt
There is a chemical potential difference because of different free energy for the different concentrations. Systems tend toward the lowest energy configuration, which occurs when there is no chemical potential difference. 

Basically, the system is thermodynamically most stable when there is no concentration gradient.