P is a hemophiliac. P received a clotting agent known as Factor VIII. In December 1991, P tested positive for HIV. P sued those providers of Factor VIII which were administered to him between 1979 and 1985. The question of proof of liability for multiple suppliers was addressed and certified to the Idaho Supreme Court; it refused to accept certification. P then argued in the alternative that alternate liability, market share liability, enterprise liability, and or concert of action would be applicable to the question of causation in this case. D filed a motion for summary judgment as to the issue of causation. The court then proceeded to analyze each of the theories of causation offered by P to the facts of the case.