From ancient times until the late 1700s, the term “speculation” was used mainly by philosophers, scientists and authors to describe conjectures about the future.
Political economist Adam Smith used the term extensively in “Wealth of Nations,” published in 1776, after seeing it used to describe lotteries and smuggling.
Rush’s terminology and his way of thinking caught on quickly.
To speculate, at its core, is to make a bet about the future based on individual calculations of the risks of tomorrow.
What we call a “mania” is just shorthand for saying that a lot of people – and machines – made the same bet, as happened in January when day traders – many of them inexperienced – drove up the price of GameStop.