Will telepathic plagiarism hold up in court in a copyright claim?
First off, plagiarism and copyright are two different things. Second, copyright infringement requires that the work be affixed in a tangible medium. Thus, something in another persons head is not copyrighted. Third, to show copyright infringement you must show opportunity to copy. If something is played on the radio and copied. it will be assume that you copied because of the wide availability. However, if something is only affixed on a sheet of paper in Fort Knox, you have to show availability to the defendant to prove copyright infringment.
