In the first section of the article, it will be shown that the central problem regarding copyright comprises solving the tension between two interests: the interest of the copyright holder in controlling the access and uses of the work by third parties and the interest of the public of accessing to it. This will be done by showing how this tension manifests itself in the concepts of authorship and public domain. Next, the article advances a reply to what is called the "skeptic's objection". Finally, by establishing the conditions that a theory must comply in order to justify copyright, the article develops a strategy for solving the tension identified in the first section.