Contrary to what professional economists will typically tell you, economics is not a science. All economic theories have underlying political and ethical assumptions, which make it impossible to prove them right or wrong in the way we can with theories in physics or chemistry.
Basically, the myth is that America has been founded on the free market; the government has done very little; it has thrived under free trade. But actually, if you look at the history, this is actually the country that has succeeded most with protectionist policies.
Imagine if all those kings and dukes hadn't commissioned those crazy cathedrals, paintings and music... we'd still be living in sticks and mud. Because none of those things made any economic sense. Human beings' capacity to 'waste time' is a miracle - but that's exactly what art is for.
I am one of the most successful economists, according to what markets tell us, though most of my professional colleagues, who are much keener to accept market outcomes than I am, would dismiss me as a crank or - the worst of all abuses among economists - a 'sociologist.'
Economics should be defined in terms of what it is about. It should be about how people produce things, how people exchange them, how people earn income, how they pay taxes, how the government provides infrastructure with tax revenue, and how it conducts monetary policy. The subject has to be defined in terms of the object of inquiry.
A lot of things that we cannot buy and sell in markets used to be totally legal objects of market exchange - human beings when we had slavery, child labour, human organs, and so on. So there is no economic theory that actually says that you shouldn't have slavery or child labour because all these are political, ethical judgments.