In the December 2009 issue of Microbe (p. 538-539), Professor Schaechter suggests that advances in microbiology can be classified as "paradigm shifts" or "paradigm drifts." The former occur rapidly and are revolutionary. The latter are the "stuff of regular science" and take time to develop. This taxonomy of change can be extended to include "paradigm lifts" and "paradigm rifts." The former would result from recognition that one concept is deserving of precedent over another, and the latter would result from recognition that a paradigm shift or drift consists of two or more concepts that are better understood and managed when considered separately. Thus, we have a syntax for describing "peaceful intellectual interludes punctuated by intellectually violent revolutions" in which one conceptual view of the microbial world is replaced or supplemented by another. I will leave it to the readers of Microbe to identify examples of conceptual change in the history of microbiology that are best described as paradigm drifts, lifts, shifts or rifts.

David Pramer
Rutgers, The State University of New Jersey
New Brunswick, N.J.