Have you actually read Kant, Locke, or any of the other enlightened thinkers? They write treatise after treatise after treatise answering this question. John Locke even answers this question several times in different treatises.
The truth of the matter is that it's better for society if everyone behaves ethically then for me to try and strong-arm my way into sex\food. If I don't have to worry about bandits I can spend my time and money on better things like programming, working, etc. It's called
the social contract.
Natural Rights are what John Locke think are the most important part of the Social contract, but he is still using the social contract to justify those rights. John Locke condemning North Korea for their lack of Life Liberty and Property is just as valid as me condemning North Korea for their lack of education. I just have the benefit of 200 years of additional books and debate regarding the issue
But, rather then reading stuff that was written over a hundred years ago by people who couldn't imagine a computer, or the internet why don't you try reading something a little bit more modern?
NonZero answers the question better then I could and was written in the late 90's.
The disagreement between you and me isn't about Locke and Kant, its whether or not property rights are natural rights. By the very nature that we have a disagreement on property rights prove my point. Property rights aren't self-evident and since they're not self-evident they're not "natural rights". What a couple of dead guys who lived a hundred years ago said about property and how it applies to the internet isn't interesting to me, but I'll answer your question regarding the two.
Kant and Locke both agree ownership is possible and necessary in a modern society because everyone agrees ownership is necessary in a modern society. They disagree about almost everything else.
The conflict
s between Locke and Kant are myriad, not only did Kant not believe property rights were natural rights, he only thought property included land, i.e. estate. Under Kant nobody could own an apple, but they could own the land where the apple came from. Kant also believed that ownership came from society, ie government. The land only became yours when society agreed it was yours. Under Kant ownership is whatever society believes ownership is. Since property rights come from society, under Kant, property can't be a natural right. Property is whatever we decide property is.
Locke on the other hand was almost completely opposite. Locke believed that land and estate couldn't be owned because nature by itself was worthless. It was only the work that made it valuable and the person who did the work owned the result. Under Locke its the migrant workers that own the field, not the landowner. If Locke was here he'd say that it's the little Asian girl that put the Iphone together who owns the Iphone, not Apple, or you or Sony. Furthermore, ownership of what you produce is an inherent right, the government can't come in and make a law saying the "owner" of the field gets the fruits of everyone's labor. By plowing that field, the plowed crop becomes yours. He also believes you can't own more then you need. He mentions that if you pick more apples then you can use and the apples go bad, then the extra apples you picked weren't really yours in the first place. Sound a bit communistic to you? There's a reason that Marx was a big fan of Locke, and his whole "workers own the means of production" is based on Locke's theory of Property rights.
There's more to it I'd recommend you actually read
Locke's 2nd Treatise on Civil Government or at the very least the
Sparksnotes to understand Locke's theory of ownership better.
But you have to remember, these works are literally hundred years old, created before the internet, computers, television or even factories were around. Locke's theory of ownership breaks down as soon as anything is created by more then 1 person. Kant's theory breaks down with anything that doesn't have a deed on it. Not only that but ALL the enlightened philosophers disagreed about the specifics of property rights. Jefferson didn't fully agree with Locke, who didn't agree with Kant, who didn't agree with Hobbes, etc. In the end what the law is regarding property and what we currently believe is just regarding property rights is more important then what a bunch of old dead guys said a few hundred years ago.