Joe Gratz has a thoughtful response to my post criticizing Edward Rothstein's NYT review of Siva Vaidhyanathan's Anarchist in the Library; below, an especially eloquent bit:

Interpolation of existing culture into new works -- either by reference or by quotation -- is inevitable. It is nothing more than historical accident that some of this interpolation is legal and some of it is illegal. The lines of copyright law are not drawn categorically between "copying" and "not-copying"; they are drawn between expressions and ideas, between derivative works and transformative works, between duplication and explication.

Copyright law separates socially useful copying from socially harmful copying. The lines drawn by current law do not recognize the way the line between "good" copying and "bad" copying has moved over the past fifty years. But make no mistake -- the line has moved, and the law must change.

Read the whole thing here.