摘要：The 'fair use" defense in copyright law shields an intellectual commons of protected uses of copyrighted material from infringement actions. In determining whether a given use is fair, courts must assess the new use's potential "effect on the market" for the copyrighted work. Fair use jurisprudence too often fails to address the complementary, network, and long-range effects of new technologies on the value of copyrighted works. These effects parallel the indirect, direct, and option values of biodiversity recently recognized by environmental economists. Their sophisticated methods for valuing natural resources in tangible commons can inform legal efforts to address the intellectual commons' "effect on the market" for copyrighted works.
