If there is one single area of economics in which path dependence is unmistakable, it is in economic geography – the location of production in space. - Paul Krugman

Feldstein pointed out that throughout the tax system inflation was turning tolerable paper tax rates into very high effective rates. Corporations, for example, were supposed to pay a tax rate of 42 percent on their profits. Feldstein calculated, however, that when the effects of inflation were taken into account, the true tax on any profits from investing in equipment was more like 75 percent.
You don't need to be a Republican to accept that tax rates this high might discourage investment and hurt economic growth. But was the interaction between inflation and investment really a major villain in America's economic difficulties? There the evidence was less clear.

Here, then, is a revised version of Marshall's rules: (1) Figure out what you think about an issue, working back and forth among verbal intuition, evidence, and as much math as you need. (2) Stay with it till you are done. (3) Publish the intuition, the math, and the evidence - all three - in an economics journal. (4) But also try to find a way of expressing the idea without the formal apparatus. (5) If you can, publish that where it can do the world some good.

… politics determine who has the power, not who has the truth.