I think, if you want to truly understand where Yanis Varoufakis is coming from in that comment, read the book Debunking Economics by Steve Keen. Although Varoufakis is probably even more critical to economic theories than Keen, the two guys agree a lot and admire each other.
Besides, Keen (and other postkeynesians) truly shows how the mathematical economics should be done, that is, by having a fully dynamic macro models with time and debt/money. I am afraid machine learning the article talks about is a similar distraction as econometrics. Unless mainstream economists will be willing to rework the theoretical foundations (give up on equilibrium, at least), and base it more on empiricism, mathematical approach, no matter how fancy, will always be a quandary.
But as other have said, the problem is that many economists are pretty much the prophets of the free market (or status quo in general). If you want to somehow claim a moral basis of society, then you can't have a model which allows multiple different solutions, and so you need to stick to equilibrium instead of allowing a dynamical solutions.
> you know not all theoretical models are equilibrium based
Depends what you mean. I would love to see a macroeconomic model, which is not just an assumption of equilibrium subjected to external shocks. I have only seen such models from postkeynesians. (Austrians do not count - they pretty much throw hands to the air and say "it does whatever it does, we cannot know anything, therefore it's OK".)
> can you rephrase it in a way that has some meaning
Well, assuming you want to show that some self-organizing system should be a moral guide, for instance, claiming that free markets lead to "efficient" (whatever that means) outcomes, then necessarily this self-organizing system has to have a stable unique outcome (which pretty much rules out chaotic behaviour that dynamical systems love to exhibit). If it had two different outcomes, then it couldn't be a unique source of morality (someone would have to come and decide which outcome is better).
For example, that's why economists, who believe in free market, cling so much to idea that there cannot be endogenous unemployment (and instead explain it as some sort of reaction to external "shock" which will eventually pass). If existing unemployment was endogenous, it would mean that at some point in the past there was a choice (bifurcation), which would set us to path of either unemployment or full employment, and the self-organizing system of free market "made" the morally wrong choice, or at least it was indifferent (meaning it is not a good moral guide).
Besides, Keen (and other postkeynesians) truly shows how the mathematical economics should be done, that is, by having a fully dynamic macro models with time and debt/money. I am afraid machine learning the article talks about is a similar distraction as econometrics. Unless mainstream economists will be willing to rework the theoretical foundations (give up on equilibrium, at least), and base it more on empiricism, mathematical approach, no matter how fancy, will always be a quandary.
But as other have said, the problem is that many economists are pretty much the prophets of the free market (or status quo in general). If you want to somehow claim a moral basis of society, then you can't have a model which allows multiple different solutions, and so you need to stick to equilibrium instead of allowing a dynamical solutions.