At last - common sense:
The word modern, first recorded in 1585 in the sense “of present or recent times,” has traveled through the centuries designating things that inevitably must become old-fashioned as the word itself goes on to the next modern thing. We have now invented the word postmodern, as if we could finally fix modern in time, but even postmodern (first recorded in 1949) will seem fusty in the end, perhaps sooner than modern will. Going back to Late Latin modernus, “modern,” which is derived from Latin modo in the sense “just now,” the English word modern (first recorded at the beginning of the 16th century) was not originally concerned with anything that could later be considered old-fashioned. It simply meant “being at this time, now existing,” an obsolete sense today. In the later 16th century, however, we begin to see the word contrasted with the word ancient and also used of technology in a way that is clearly related to our own modern way of using the word. Modern was being applied specifically to what pertained to present times and also to what was new and not old-fashioned. Thus in the 19th and 20th centuries the word could be used to designate a movement in art, modernism, which is now being followed by postmodernism. — https://web.archive.org/web/20080622132303/http://www.bartleby.com/61/28/M0362800.html
