Take for instance, there is no social dynamics rule you can state like the rule of supply and demand, or the principle of time preference (that ceritas paribus, people prefer things sooner than later). These are not just 'social dynamics'.
It's not human nature either. I highly recommend that you don't brush it off that quickly.
There are two kinds of 'body movements' by humans, 'involuntary' or 'non-rational', like sneezing, or tripping, vs voluntary or rational, like you choosing to brush your teeth, or driving a car or negotiating a contract.
If a human says that he doesn't want to divorce his wife but he can't feel the same passion towards her, or if someone is trying to lose weight but is unable to stop eating, then trying to understand that action is psychology.
However, if we just stop to the fact that if you perform an action, irrespective of your 'stated' reasoning behind it, it does demonstrate something.
When we look at these actions which are pertinent to monetary aspects of those rational or voluntary actions, we find out that we can build a whole system of science (or logic, if you don't like saying it's a kind of science), which leads us to other conclusions.
For instance if you say that you would love to spend the spring break in France, but then when the time comes, you find out that tickets are cheaper for Mexico, and instead you spend it in Mexico, then that means that your demonstrated preference was to have that extra money and do other things with it in Mexico, instead to have less money in France (irrespective of what you said).
What this means is that if prices of Mexico tickets were changed and it becomes as expensive as tickets to France, then you will change your decision also (though you don't have to, in which case we will learn that you actually didn't care about going to France anyways).
Either way, when you build a system of all the logical inferences, like in Mathematics, smaller concepts and axioms can lead you to build other complex mathematical conclusions, you have the same thing in economics (which leads you to the concepts of interest rates, prices, supply and demand, autistic intervention, binary intervention, triangular intervention etc).
You can't say that it's all just social dynamics.
Take for instance, there is no social dynamics rule you can state like the rule of supply and demand, or the principle of time preference (that ceritas paribus, people prefer things sooner than later). These are not just 'social dynamics'.