> we couldn't see germs with a microscope doesn't mean they weren't effective in our lives. And because we couldn’t see them we misattributed their effects and

> we couldn't see germs with a microscope doesn't mean they weren't effective in our lives. And because we couldn’t see them we misattributed their effects and treated people with bloodletting. Confidently declaring your understanding of an unseen enemy and applying seemingly-appropriate countermeasures is likely to be harmful.