John Paul Stevens,
Sony Corp. of America v. Universal City Studios…
“ The purpose of copyright is to create incentives for creative effort. Even copying for noncommercial purposes may impair the copyright holder’s ability to obtain the rewards that Congress intended him to have. But a use that has no demonstrable effect upon the potential market for, or the value of, the copyrighted work need not be prohibited in order to protect the author’s incentive to create. The prohibition of such noncommercial uses would merely inhibit access to ideas without any countervailing benefit. ”
