I believe in the importance of copyright, but I also think most people have a perverse notion of what is copyright and intellectual property.
First, intellectual property is not the same as physical property; physical property is scarce and rivalrous, whereas intellectual property is not. Physical property, such as land or money, cannot be produced. Money can be printed, but the more money there is in circulation the less value each piece of currency has, so one could say that the total value of a currency cannot be produced. The same can be said for land, which obviously cannot be produced. This means that the more land I own the less land there is for everyone else. Land and money are also rivalrous, meaning that if I use them for one thing i cannot use it for another. Intellectual property has no such constraints, so it does not entail the same rights as physical property.
Second, for those in the U.S., the founding fathers didn't treat IP the same as physical property. The constitution gives congress the power to grant authors and inventors exclusive rights over their works "for limited times only." The purpose of the copyright clause was not to ensure property rights, but to encourage the creation and dissemination of information. The exclusive right over works encourages creation by giving authors monetary incentive to create, and the limited duration of the copyright ensures that the work will eventually fall into the public domain, where it can more easily and cheaply be distributed. The U.S. government has never recognized property as entailing absolute rights, and I'm sure the same can be said for other countries. For instance, the principle of eminent domain gives the government the power to seize private lands for public benefit.
Finally, i do not see the logic in saying that descendants have the right to control and profit from the ips of their parents or grandparents. Taking physical property requires force; reproducing an ip deprives the descendant of nothing but control over the ip. Physical property also requires some sort of investment to maintain it, whereas ip does not. If i inherit land, I have to do something with that land to get benefits out of it. Otherwise, the land becomes a liability either because of taxes, the need to maintain it, or the need to protect it from trespassers. The same can be said of money. If I inherit money and do not invest it, I will eventually spend all the money. With physical property, the inheritor must add value or the inheritance becomes a liability. Inheriting an IP requires no investment. If the IP has no monetary value, then it is being withheld from the public which possibly could reimagine or revise the IP. If it still has monetary value, then its just free money for the inheritor. My overall point is that most of our rights exist not because of some eternal truth, but because recognizing these rights is in the best interest of society.
As far as the duration of copyright, I cannot say how long it should be. In principle I am opposed to the sonny-bonno act because of the corruption it represents. This law was not passed for the good of the public or the economy or the creators; it was passed at the behest of major entertainment corporations by their paid-for politicians. The current copyright regime is antidemocratic in nature, but I do not believe that it will lead to the fall of civilization. Pop music and reality tv will do that.
Finally, I know that half the people who see this post will not read of all it; instead these high and mighty oh so wise and righteous folk who have everything and everyone else figured out because they've had to pay a few bills in their life will assume I'm just some pimply-faced unemployed teenager living in his parents basement who just wants free stuff. Its surprising. I thought there was less snark and smugness at Mobileread.
Here are some links for those who want to know where I stole my ideas.
http://www.publicknowledge.org/node/958
http://en.wikisource.org/wiki/Eldred...Dissent_Breyer