In 1962, Thomas Kuhn wrote a book of seminal importance, The Structure of Scientific Revolution, wherein he introduced the concept of “paradigm shift.” Kuhn proposed that science advances through a “series of peaceful interludes punctuated by intellectually violent revolutions,” revolutions in which “one conceptual world view is replaced by another.” Paradigm shifts occur rapidly; other significant insights take their time in developing and are the stuff of “regular” science. Borrowing from the language of influenza virology, I will call the latter “paradigm drifts.” How do these concepts apply to the microbial sciences?