Property rights originally existed to ensure the proper use of things which cannot be divided without being decreased. For example, if I have a loaf of bread and I give you half of it, then I have only half a loaf left. You have profited at my expense. That is why the law insists that such transactions must be consensual. I must give the bread to you out of the goodness of my heart or exchange it for something that I value more, for example money. You cannot simply take it from me by force or trickery. If you do, I can report you to the police and you will be punished and forced to return my property.
Ideas are quite different. If I have an idea and I choose to share it with you, you have the idea but I still have it too. My possession of my idea has not been diminished in any way. Even if you acquire my idea against my will by spying on me, you can't thereby take it away from me. I can reasonably take legal action against you for violating my privacy, but it's ridiculous to say that my property rights have been violated when I still have the thing you supposedly robbed me of.
Where then do the rights that we group together as intellectual property actually come from?
Patents go back the furthest. They were invented by that canny monarch James VI of Scotland and I of England. James wanted to encourage invention for the general good of society. He saw that inventors are mostly driven by the desire to make money, but that it actually costs money to develop an invention. The inventor hopes to recover these costs and then make a profit by selling either the invention itself or a product that the invention would allow him to make. But there is always a risk that somebody else, who has not had to pay the development costs, will undercut his price, steal his markets, and so rob him of his profits. The next time that inventor has a good idea, he might either not develop it at all, or develop it in secret. The secret would eventually die with him. Either way society loses out.
The King's solution was to publish "Letters Patent of Invention", that is open letters addressed to whom it might concern, granting the inventor a 16-year monopoly on working his invention, which would allow him to make a handsome profit. In return, he was required to provide a description of his invention (a Patent Specification) sufficiently detailed that any person "skilled in the art" could learn how to work it. At the end of the 16 years, the monopoly would lapse and the invention would become part of the general knowledge of society.
The American Founding Fathers thought this such a good idea that they incorporated it into their constitution, giving Congress the right to grant monopolies to inventors in order to encourage invention. But neither King James nor the Founding Fathers ever described patents as being for the protection of some preexisting property right.
Copyright dates from the 18th century, the first copyright act appearing in the reign of Queen Anne. It covered written works only, but the idea came to be extended to music and the visual arts. As with patents, the purpose was to encourage innovation and not to protect some nebulous kind of property.
In the Middle Ages, there was no copyright at all because none was needed. People who wanted to write books simply wrote them. No one imagined that any kind of financial reward was necessary. The books were reproduced by manual copying, and copyists often made corrections or inserted new material. Books were held to belong to the sum total of recorded human knowledge, so keeping them up to date was considered important. A certain amount of music and art was paid for directly by aristocratic patrons or by the Church, but many people painted, composed or played music in their spare time without receiving a penny for it.
This marks an important difference between inventors and other kinds of creative people: a composer might like to make money out of his music so that he can give up his day job, but he will continue to compose whether he makes money or not. For inventors, the making of money is the main purpose and they will give up inventing things if they cannot make a profit out of it. This explains why copyright in creative work arrived so much later than patents for inventions.
It was the invention of the printing press that changed everything . The first printers worked directly for authors, who ordered a certain number of copies of their work, paid for them and then sold them. However authors were often short of money, so if the printer thought the work would sell well, he might buy it off the author, print it and sell it himself. In this way printers gradually metamorphosed into publishers. They became the first of a whole series of middlemen who made possible the distribution of creative works to a wider audience than had ever been possible before.
For example, there were orchestras to give public concerts of musical compositions, and concert halls and opera houses where they could do this. There was printed sheet music as well as printed books. Before the advent of recorded music, there was a huge market for piano transcriptions of orchestral pieces. There were art galleries where pictures could be displayed and sold, and later there were studios for recording music and factories for pressing records. All this had to be paid for. Creative people might be willing to create for nothing and maintain a day job to pay the bills, but the layer of useful middlemen who mediated between the creator and his audience were businessmen, who needed to make a profit to survive. It was to protect them, and not to protect writers or musicians, that copyright laws proliferated.
To a certain extent, this has become outdated. Any geek can now have in his bedroom electronic recording equipment that surpasses what was available in the recording studios of the 20th century. Podcasts and vlogs can be put straight onto the Internet. Books can be self-published on a variety of sites and printed on demand. Middlemen are no longer needed. It is ironic that as new technology makes it increasingly difficult to police copyright laws, it also makes them increasingly irrelevant.
If patents were designed to encourage invention, and copyright to ensure the survival of publishers and similar middlemen, trademarks originally existed for the protection of the public. The basic idea is that, if a particular manufacturer produces superior goods and people want to buy them for that reason, they should be able to feel confident that they are getting the genuine article and not a poor imitation. Again, this has nothing to do with property as commonly understood. Forging a pair of Ugg boots is much more akin to forging money than it is to stealing. It is (in theory anyway) the buyer of the boots who loses out, and not the trademark owner.
However the situation has become complicated by the modern mania for "designer goods" which has led to the label becoming more valuable than the item it is attached to. There are now many people who buy goods that they know are forgeries because they want the label and they want it cheap. They are not looking for the high quality that the label originally stood for; they just want something good enough to fool their friends.
Honest dealing requires the interests of the parties to be opposed. For example, a man who sells antique furniture may want to sell you a fake but you almost certainly want the genuine article. So you will immediately be on your guard if the price seems suspiciously low or if the police have announced that forged goods are currently being offered on the market. Equally it is in the interests of the vendor to ensure that the payment you offer is good money. With fake designer goods the interests of the buyer and the seller too often coincide, which is why this trade is now completely out of control.
As a result, the trademark owner loses out on sales and is justifiably aggrieved. This has led to the paradox that the type of "intellectual property" which was originally least like property has now become the most convincing example of the idea.
Both copyright and trademarks have probably reached their "sell-by date". Copyright increasingly makes no sense in a world where creative people can so freely share their ideas, without any need for profits to be made in order to fund the process, and trademarks have been effectively emptied of their original protective function by the greed of companies who have marketed the label rather than the goods. Only patents still have some point (especially in fields like pharmaceuticals where development costs are high), but we can have patents, as we did for centuries, without talking nonsense about intellectual property.