“The inverse relationship between quantity demanded and price is the core proposition in economic science, which embodies the presupposition that human choice behavior is sufficiently relational to allow predictions to be made. Just as no physicist would claim that “water runs uphill,” no self-respecting economist would claim that increases in the minimum wage increase employment. Such a claim, if seriously advanced, becomes equivalent to a denial that there is even minimal scientific content in economics, and that, in consequence, economists can do nothing but write as advocates for ideological interests. Fortunately, only a handful of economists are willing to throw over the teachings of two centuries; we have not yet become a bevy of camp–following whores. “
That’s a favorite quote from James M. Buchanan. He wrote that in the 1990s in response to a Wall Street Journal interview in which the disemployment effect of minimum wage legislation was questioned.
The theoretical case that minimum wage laws adversely affect low-skilled workers is as sound as anything else in economics. The empirical evidence is also as sound as the empirical evidence for “dog bites man.” What makes the news is when “man bites dog.” That exception does not invalidate the general case that dogs bite men.
The inverse relationship between quantity demanded and price is depicted as downward-sloping demand schedules. Demand slopes downward as certainly as water flows downhill. What justifies that claim? Because quantity demanded falls as the price rises. We know this from our own experience: we buy less when price goes up and buy more when price falls.
Granted, there are curiosities in price theory — Veblen goods (for which demand increases as the price increases, e.g. luxury goods), backward-bending supply curves, Giffen goods, et cetera.
Identifying curiosities and corner cases, and using them in support of ideologically-motivated policies is tantamount to joining a bevy of camp-following whores. Journalists often do. Economists? A few outliers do, and some even get recognized by the economics “Nobel” prize committee.
For a bit of context, read this March 2019 The Nation piece “Alan Krueger’s Radical Empiricism.” Note that I am not endorsing the content of the article; I’m just using it to provide context. And here’s a bit more context:
 Investopedia on giffen goods:
Giffen good are a rarity in economics because supply and demand for these goods is opposite of standard conventions. Giffen goods can be the result of multiple market variables including supply, demand, price, income, and substitution. All of these variables are central to the basic theories of supply and demand economics. Giffen goods cases study the effects of these variables on low income, non-luxury goods which result in an upward sloping demand curve.
See also their description of Veblen goods.