Then, perusing How Rich Nations Got Rich and Why Poor Nations Stay Poor by Erik S. Reinert, I come across this passage on page 75:
Not only was it a necessary precondition for wealth to have a large and growing population, the concentration of this population was also exceedingly important. English economist William Petty (1623-87) therefore suggested moving the population of Scotland and other then peripheral areas to London, where the people would contribute much more to economic growth than they were able to do in the empty fringes of the island.The import of Petty's recommendation is not what is at issue.
My coming across an obscure British economist of 350 years ago in the space of week is. Now I have hundreds of books of English history, economic development and economic history. It is not improbable that I have come across Petty before and am simply failing to recall him.
Still, his popping up is an example of the Frequency Illusion or the Baader-Meinhoff phenomenon, described, colloguially in the 1987 movie, Repo Man,
A lot of people don't realize what's really going on. They view life as a bunch of unconnected incidents and things. They don't realize that there's this, like, lattice of coincidence that lays on top of everything. Give you an example, show you what I mean: suppose you're thinkin' about a plate of shrimp. Suddenly someone'll say, like, "plate," or "shrimp," or "plate of shrimp" out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconsciousness.I remember little else of the movie these near thirty years later, but that scene stuck for describing a known but little discussed phenomenon. The humorous aspect, of course, was that throughout the remainder of the movie, "plate of shrimp" made numerous sotto voce cameos as background.