Fair use in copyright law
Fair use recognizes that there are societies — society can benefit from uses of existing copyrighted works. The obvious examples are in criticism, in teaching, in scholarship. If you’re going to criticize a book, you probably need to quote sentences from the book or describe what’s going on in the book, and that will involve reproducing the copyrighted work, in any rate, to a small extent. And when you do that, there are various tests that can be used, but that is permitted. That is beneficial to everybody, and so that is not deemed to be a copyright infringement. The law means — and it is no different from it is in the real world. You can’t take any more or any less. And generally speaking, what you’re looking at in fair use is you’re taking a small part of an existing work and using it in what is called a transformative manner to create something else.