(p. 54) Coffee is a stimulant that has been clinically proven to improve cognitive function—particularly for memory-related tasks—during the first cup or two. Increase the amount of “smart” drugs flowing through individual brains, and the collective intelligence of the culture will become smarter, if enough people get hooked. Create enough caffeine-abusers in your society and you’ll be statistically more likely to launch an Age of Reason. That may itself sound like the self-justifying fantasy of a longtime coffee-drinker, but to connect coffee plausibly to the Age of Enlightenment you have to consider the context of recreational drug abuse in seventeenth-century Europe. Coffee-drinkers are not necessarily smarter, in the long run, than those who abstain from caffeine. (Even if they are smarter for that first cup.) But when coffee originally arrived as a mass phenomenon in the mid-1600s,it was not seducing a culture of perfect sobriety. It was replacing alcohol as the daytime drug of choice. The historian Tom Standage writes in his ingenious A History of the World in Six Glasses:
The impact of the introduction of coffee into Europe during the seventeenth century was particularly noticeable since the most common beverages of the time, even at breakfast, were weak “small beer” and wine. . . . Those who drank coffee instead of alcohol began the day alert and stimulated, rather than relaxed and mildly inebriated, and the quality and quantity of work improved. . . . Western Europe began to emerge from an alcoholic haze that had lasted for centuries.
Johnson, Steven. The Invention of Air: A Story of Science, Faith, Revolution, and the Birth of America. New York: Riverhead Books, 2008.
(Note: ellipses in original.)