Ah, were the Romans to have had antibiotics, eh?
ADDED: The Romans did apparently have some knowledge of antibiotics without presumably understanding the mechanisms or refining them. Per Wikipedia and other sources: "Antibiotics have been used since ancient times. Many civilizations used topical application of moldy bread, with many references to its beneficial effects arising from ancient Egypt, Nubia, China, Serbia, Greece, and Rome."
> ADDED: The Romans did apparently have some knowledge of antibiotics
Fascinating. Worth looking into.-
Sometimes, all it took was one person noticing something (midwives who wash their hands post partum tend to have better outcomes, farmers near cows get less sick, or not at all ...)
... but, you raise another good point: First principles, the search for the facts. Benefits at scale come with, consistently, wanting to go from observation, to general principles, to particular application, to mass application ...
... and, maybe, it took rational thought and the scientific method to get there.-