The aspects of copyright law designed to motivate creators to create.
Copyright law grants to the rights-holder, for a limited time, a monopoly over uses of the copyrighted work. Since monopolies are usually considered inefficient, the justification for doing this is usually described as providing the necessary incentives to creators to get them to create. That is, without the incentive of being able to benefit economically by exploiting control of the work, why would an artist create? This is often called the economic theory of creator incentives, or something similar. The assumption is that there is a net gain for society. For example, the Copyright clause of the U.S. Constitution reads “To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.”
The incentive driven view of copyright and creation has come under some criticism for failing to take into account the many different motivations artists have for creating their work, some of which are not financial at all. Other critics point out that even if incentive theory is accurate, extremely long copyright terms do not increase the economic or monetary value of copyright, arguing against term extensions.