Patents and copyrights are so critical to a capitalist system that protections for them are specifically enshrined in the Constitution. While there are those who would argue that copyrights and patents are enforced too strictly and for too long today, a society with no protections would cease to innovate and would stagnate economically and perhaps culturally.
Patents and copyrights are necessary in order to reward entrepreneurs for the time and money they spend on their research and development. If these protections are not available, people and firms will not try to innovate. For example, let us imagine there were not protections for a new drug. As soon as a drug was developed, any company could copy it and start making it themselves. In such a situation, there would be no incentive for any firm to do the research necessary to create a new drug. They would be stupid to do such a thing because they would put in all the resources and then some other firm would come in and be able to undersell them because it had not had to spend any money on research.
If there were no copyright or patent protections, firms would cease to innovate and our economy would stagnate.