Survival of the Sudsiest, or George Will happens upon the fifth law of thermodynamics.

“The search for unpolluted drinking water is as old as civilization itself. As soon as there were mass human settlements, waterborne diseases like dysentery became a crucial population bottleneck. For much of human history, the solution to this chronic public-health issue was not purifying the water supply. The solution was to drink alcohol.”

Often the most pure fluid available was alcohol — in beer and, later, wine — which has antibacterial properties. Sure, alcohol has its hazards, but as Johnson breezily observes, “Dying of cirrhosis of the liver in your forties was better than dying of dysentery in your twenties.” Besides, alcohol, although it is a poison, and an addictive one, became, especially in beer, a driver of a species-strengthening selection process.

This fits right in with concepts from Jared Diamond’s Guns, Germs and Steel, in that civilization which didn’t develop the kind of population densities (i.e. towns) compelling people to drink alcohol did not see the genes for alcohol tolerance selected for (along with diseases that mutated and jumped from domesticated animals to humans in these regions with high densities)