"The protection given to copyrights is wholly statutory, and, in a case like this, in which Congress has not plainly marked the course to be followed by the judiciary, the Court must be circumspect in construing the scope of rights created by a statute that never contemplated such a calculus of interests based on technological advances.In proceeding, the Court must balance the encouraging and rewarding of authors to create new works with the public good.This case does not fall in the category of those in which it is manifestly just to impose vicarious liability because the contributory infringer was in a position to control the use of copyrighted works by others and had authorized the use without permission from the copyright owner.In this case, the only contact between Defendant and the users of the VTR's occurred at the moment of sale.However, there is no precedent for imposing vicarious liability on the theory that Sony (Defendant) sold the VTR's with constructive knowledge that its customers might use the equipment to make unauthorized copies of copyrighted material." - Explain what this quote mean.