The current Patent Law does not provide a cause of action against an indirect infringer. Accordingly, whenever a patent owner intends to sue a person selling an unpatented component for use in a patented invention, he/she would have to resort to the Civil Code in which the act of "aiding and abetting" is specified as a tort. According to the relevant stipulations in the Civil Code, however, only when a principal infringer has been held liable, would the instigators or accomplices be deemed to be joint tortfeasors and jointly liable for injury. Besides, the so-called all element rule which is generally used in interpreting the claims' scope sometimes makes it quite difficult, if not impossible altogether, for a patent owner to claim damages from the manufacturer of a component which is essential in the practice of the patented invention.