I was just revisiting Reagan sitting down with William F. Buckley Jr. on Firing Line, and the ex-president credited one Ibn Khaldun for inventing supply-side economics. Video:
Who is Ibn Khaldun? He was an Arab scholar born in modern-day Tunisia many centuries ago. He wrote a book called The Muqaddimah in 1377, which is apparently the text Reagan gleaned his ideas from. Khaldun wrote:
"It should be known that at the beginning of the dynasty, taxation yields a large revenue from small assessments. At the end of the dynasty, taxation yields a small revenue from large assessments."
And I bet most of you believe the creation myth about supply-side originating with Art Laffer scribbling on a napkin. :)
Other things Khaldun apparently invented before the West rediscovered it: the supply and demand curves later reinvented by Alfred Marshall, Biblical criticism, the scientific method applied to sociology and history, and the theory of evolution. He also anticipated much of the Enlightenment. He was also apparently a Cornucopian, rather than a Malthusian, because of his beliefs that population growth begets more wealth in a society.
In the interview with Buckley, Reagan stresses discovering Khaldun "in my studies." He apparently discovered the scholar independent of his political advisers as governor and president. It makes me wonder what other texts he may have gone through.