[4V50 Gary]

Fair use doctrine allows for the use of another's material. It's the "balance" Congress felt was necessary to further literary, scientific or technological knowledge. Without it, there's no progress as you cannot build upon the design or knowledge of another. Fair use is balanced against the proprietary interest of the copyright or patent holder. At what point is the copyright or patent holder disenfranchised of the rights such that his interest is not protected? Small use which do not infringe upon that right of the patent or copyright holder are permitted by the courts.