Copyright is not a property right. It is a limitation of property rights. Copyright is a government-sanctioned private monopoly that limits what people may do with things they have legitimately bought.
When I buy a chair, I hand over money and I get the chair and a receipt. This chair has been mass-produced from master data at some sort of plant. After money has changed hands, this particular chair is mine. There are many others like it, but this one is mine. I have bought one of many identical copies. The receipt proves it.
As this copy of the chair is mine, exclusively mine, there are a number of things I can do with it. I can take it apart and use the pieces for new hobby projects, which I may choose to sell, give away, put out as exhibits or throw away. I can put it out on the porch and charge neighbors for using it. I can examine its construction, produce new chars from my deductions, and do whatever I like with them, particularly including selling them.
All of this is normal for property. It is mine; I may do what I like with it.
As a sidetrack, this assumes that there are no patents on the chair. However, assuming that the invention of the chair is older than 20 years, any filed patents on this particular invention have expired. Therefore, patents are not relevant for this discussion.
Now, let’s jump to what happens when I buy a movie.
When I buy a movie, I hand over money and I get the DVD and a receipt. This movie has been mass-produced from master data at some sort of plant. After money has changed hands, this particular movie is mine. There are many others like it, but this one is mine. I have bought one of many identical copies. The receipt proves it.
Despite the fact that this copy of the movie is mine, exclusively mine, there are a number of things that I may not do with it, prohibited from doing so by the copyright monopoly held by somebody else. I may not use pieces of the movie for new hobby projects that I sell, give away, or put out as exhibits. I may not charge the neighbors for using it on the porch. I may not examine its construction and produce new copies. All of these rights would be normal for property, but the copyright monopoly is a severe limitation on my property rights to what I have legitimately bought.
It is not possible to say that I own the the DVD when viewed in one way but not when viewed in another. There is a clear definition of property, and the receipt says I own the DVD in all its interpretations and aspects. Every part of the shape making up the DVD is mine. Copyright, however, limits how I can use my own property.
This doesn’t inherently mean that copyright is bad. It does, however, mean that copyright cannot be defended from the standpoint that property rights are good. If you take your stand from there, you will land in the conclusion that copyright is bad as it is a limitation of property rights.
As Christian Engström writes, defending copyright with the justification that property rights are sacred is quite like defending death penalty for murder with the justification that life is sacred. There may be other, valid, justifications for defending copyright and these limitations of property rights — but that particular chain of logic doesn’t hold.
A quick history lesson here as to why copyright is commonly (and deliberately!) confused with property rights:
When the copyright monopoly of the Stationers’ Company had been terminated in the United Kingdom in 1695, the publishers lobbied heavily to have their lucrative monopoly reinstated. Parliament, however, were not too keen on that idea. The monopoly had been a central point of control used for censorship for 148 years, and the British Parliament attached great importance to not creating any mechanism that could be used to suppress free speech, at least not using that particular method.
The publishing lobby responded by suggesting that writers should “own” their works. In doing so, they killed three birds with one stone. One, Parliament would be assured that there was no central point of control which could be used to censor. Two, the publishers would retain a monopoly for all intents and purposes, as the writers would have nobody to sell their works to but the publishing industry. Three, and perhaps most importantly, the monopoly would be legally classified as Anglo-Saxon Common Law rather than the weaker Case Law, and therefore given much stronger legal protection.
They publishing lobby got as they wanted, and the new copyright was re-enacted in 1709, taking effect on April 10, 1710.
I sometimes refer to this as the copyright lobby’s first major legal victory, when the monopoly was reclassified into Anglo-Saxon Common Law due to that particular piece of footwork and deliberate misrepresentation as property.