There exists a fundamental mechanism in nature with its roots in causality.
Sergio Pissanetzky
532

Good question. For example if you push a wall the wall pushes back with the same force. It works in the other direction as well. If the wall is falling and pushes you, your body pushes back. It’s a mechanical effect. But it’s not what I mean by “action.” Action is travelling energy, and I am referring to free energy in a system of interest that is travelling from place to place and then reaches the boundary and “leaks” from your system into another system. This is a flow of energy and is regulated by Thermodynamics. If your system is hotter than the other, it looses energy and its entropy, or disorder, also decrease.