Many people have written about this. Alessandro Rubini wrote thusly:
Actually, "intellectual property" is a buzzword. There is no "IP law" to my knowledge, but there are laws about copyright, patents, trademarks.
"intellectual property" is the term information owners use to spread the idea that owning information is a natural thing just like private property (yes, some of you may disagree, but you get my point anyways).
The truth is different: copyright, patents, trademarks are legal hacks designed to help society as a whole; they are not natural rights and they must not be lumped together as they act in different realms with different means.
The Free Software Foundation has an entry on this topic. There is also a compact essay on gnu.org.
Protection of ideas and expressions should benefit the general public and the progres of society as a whole. As such, there should be limits to this protection, so that remixing the old into the new is facilitated. Progress always is about remixing.
Remember that products of the mind (ideas, expressions of ideas, encodings of ideas) are non-rivalrous goods. There are special laws to grant certain limited rights to people publishing such ideas. In order to foster progress, such rights must necessarily decay. Otherwise the reservoir of ideas available for remixing will shrink. There is an infinity of ideas and expressions out there, but each and every one of them builds on older ideas. This holds true for literature, music, mathematics, software, inventions, and basically all human enterprises of the mind. In this respect it cannot reasonably be compared to physical products.
The concept of intellectual property as something that can be amassed just as physical property (a rivalrous good) is wrong. The implication that it is a good idea to increase the similarity in legal status between physical property and ideas and the expression of ideas to ever greater extents is preposterous.