This excellent article on unconscious plagiarism, known as “cryptomnesia,” exposes the exact reason why Copyright should only extend to protect against actual copying.
“When people engage in creative activity, they are so involved in generating or coming up with something new or novel that they fail to protect against what they previously experienced,” said Marsh. Over the last 20 years, Marsh has designed numerous models for studying cryptomnesia in the lab. An early study involved asking subjects to work with an unseen “partner” (actually a computer) to find unique words in a square array of letters, similar to the game Boggle. A short while after completing this task, the researchers asked each participant to recall the words they had personally found, and to generate new words neither the participant nor the participant’s partner had previously been able to find.The subjects plagiarized their partners roughly 32 percent of the time when trying to recall their own words, and up to 28 percent of the time when attempting to find previously unidentified words in the puzzle. Not only was plagiarism rampant, many subjects who plagiarized also checked a box indicating they were “positive” their answers had not previously been given by their partners.
Copyright is premised on the notion that something with Copyright cannot preclude the publication of similar works that are the result of the activity known as “independent creation,” as courts have noted that there is no novelty requirement in Copyright like there is in Patent law. Allowing an individual to have a monopoly on an idea or form of expression would kill the First Amendment and the rights appertaining thereto just as fast as a speech licensor.