Liberal economics is not a science but based on bad philosophy and assumptions about human psychology, dreamt up by "economists" with no background in psychology nor based on any empirical research, which have never been demonstrated in practice. Not only aren't they demonstrated, but they build mathematical models on top of these assumptions, but if the assumptions are meaningless, all the models are meaningless.

If you point this out, they will tell you, "sure, these assumptions aren't literally true, but they're just approximate." But in any rigorous science, if you approximate something, you're expected to calculate your error bars, so you can have an idea of just how approximate it is. If you don't, then for all you know, the error bars can be so big it has no relation to the real world. No liberal economist can tell you any way to actually determine how inaccurate their assumptions are, so you end up with a lot of maths, but none of it points back to anything real.

Conveniently, though, their maths just so happen to always work out to prove the conclusions they started with: free markets are inherently good, state controls are inherently bad. They have never updated their theories after witnessing their complete failure in eastern Europe, they in fact try to rewrite history to pretend like it was state controls that destroyed Russia's economy and free market anarchy that saved China's, which, as this video shows, the most basic overview of the facts shows to be the exact opposite of what happened.

—aimixin