There’s a common misconception about copyright law: Once a work is copyrighted no one else can get a copyright on it. This myth is used by some people (see the comment by PaulT at this article on techdirt.com) to argue that copyright law stifles creativity.
The tech dirt article cited above disparages the 6th Circuit for declaring that copying a 2-second clip of song and looping it is copyright infringement (in Bridgeport Music, Inc. v. Dimension Films, 410 F.3d 792 (6th Cir. 2005)).
But the logical question is: Why did the infringer feel compelled to copy someone else’s 2 seconds of music instead of creating his own 2 seconds worth to loop on?
In addressing that question the commenter writes, “Then, most likely get sued anyway because your tiny guitar riff resembles another. Even if you hadn’t actually copied the original and came up with a similar riff on your own.”
The fact is that copyright accrues to “original works of authorship,” which means if you create a tune without knowing anything about one that is closely (or even exactly) like yours, you have created a copyrighted work and you are not an infringer.
The idea behind copyright law is to encourage new works and discourage copying. Wouldn’t it have been more creative of the infringer to…well…actually create?” Or was he merely trying to co-opt someone else’s fame?
Don’t confuse the strict liability rules of patent infringement and trademark infringement with the anti-copying rules of copyright infringement.