The language of science is always so amazingly precise . . . except when it isn't. Consider, for example, the word "life." Scientists have long struggled to determine exactly what qualifies as "life." For instance, are viruses “alive?” In the October 23, 2008 edition of Nature (available only to subscribers online), an article titled "Disputed Definitions" considers other often-used disputed terms. The article is divided into sections written by specialists from the relevant disciplines. The subtitle of the article is "Nature goes in search of the terms that get scientists most worked up." Consider how often you encounter the following disputed terms. Consider "paradigm shift," made popular by Thomas Kuhn in his often-cited 1962 book, The Structure of Scientific Revolutions. Kuhn argued against the then-popular view that science marched incrementally toward the truth. Sometimes, "normal science" doesn't explain all of the phenomenon, straining a prevailing scientific theory. If the strain of accommodating evidence is great enough "eventually some new science comes along and overturns the previous consensus. Voila, a ‘paradigm shift.’" The often-used term "paradigm shift" is used in at least two ways, however. In its broad sense it encompasses the "entire constellation of beliefs, values, techniques and so on shared by the members of a given community." In the narrow sense, it refers to "concrete puzzle-solutions." Another often-debated (and currently fashionable) term is "epigenetic."