Accoding to the United States Patent and Trademark Office's website (http://www.uspto.gov):
"A patent for an invention is the grant of a property right to the inventor"
But then it goes on to say:
"The right conferred by a patent grant is, in the language of the statute and of the grant itself, “What is granted is not the right to make, use, offer for sale, sell or import, but the right to exclude others from making, using, offering for sale, selling or importing an invention."
Why is this even be legal? By every principle of liberty, freedom and democracy I know of this should be unconstitutional. No law should ever give any governmental agency the power to grant any person or organization the right to infringe on the right's of others. Ideas and inventions (intellectual property) should be free (as in freedom).
Free markets depend on competition. Not just a little competition, a lot of competition. But we don't have a free market, we have a mixed market which is mostly regulated and engineered by government agencies and large businesses routinely engaged in collusion. Pentents are the reaseon why. Patents bypass the market and eliminate competition instantly. Patents are the reason our economy is dominated by large businesses who make life hell for small businesses.
Small businesses represent the power and independance of families and individuals. Most people are unable to employ themselves because of patent laws. The only practicle source of income for most Americans is employment. Once employed, the government has us right where they want us and can easily garnish from our wages whatever taxes they want.
Thus, the people are stripped of their power to keep government in check and made as slaves to the plutocrats who run the government through the electoral college. Without patents, the people would be able to employ themselves and they would have the power to keep government in check. They could decide whether to support their government or not by whether they approve of it or not. It all comes down to ideas. The market and the people are only as free as our ideas.