We are going to contrast the way Locke’s chapter on property rights is taught in philosophy classes with what an economist finds in it.
The philosophy version is that Locke is an early libertarian who is arguing for natural property rights. As far as this way of reading Locke is concerned, the chapter could pretty much end around §31 or, if you want to stretch it out, §39.
To be fair, §39 really does appear to give an answer the question that he originally posed for himself, namely, how did we come to have private property when God gave the Earth to mankind in common, “without any express compact of all the commoners” (§25). It’s a natural place to think “he’s done now.”
And yet Locke himself does not stop at §31 or even §39. He goes all the way to §51. Why?
What Professor Brown finds is an anticipation of distinctions that economists would develop after Locke’s time. Locke treats acorns as consumption goods (see §31), land as productive inputs (§§32–44), and money as a store of value (§45–51).
Locke was not asking the kind of questions that economists ask. He had moral commitments to the propositions that it is wrong to acquire goods and let them spoil and that it is wrong to acquire property without leaving enough and as good for others. His question was how private property could be compatible with these commitments. It was in the course of answering this fundamentally moral question that he developed these concepts that economists find so useful.
These readings are about property rights. Chapter 4 of the First Treatise disputes Sir Robert Filmer’s argument that God gave Adam property rights over everything on Earth. Most of the chapter is taken up with interpretations of the Bible; I left that out. The part that I included claims that even if God had given Adam property rights to the whole world, he would not be allowed to exclude others from using what they need. The point is general: no one’s property rights, even if they come from God, can give them the right to exclude people from using what they need.
Chapter 5 is Locke’s celebrated theory of natural property rights. It falls into three parts.
The problem (§25). He assumes that God gave the world to people in common and so he has to explain how private ownership emerged out of common ownership. Unlike some of his contemporaries, he says that he will explain how this happened without supposing that the common owners consented to the institution of private property.
The labor theory (§§26–30). People come to own parts of the earth’s resources by mixing them with something else that they own, their power to labor. Locke maintains that they can do this without first getting the consent of the common owners of the earth’s resources.
Objection: some people could come to own too much. The rest of the chapter is devoted to answering this (§§31–51).
Locke’s answer to the objection involves a combination of moral principles and factual descriptions of appropriation in different societies.
The chief moral principle Locke asserts is that people cannot acquire property rights beyond what they can use; in other words, no spoilage is allowed (see §31, §§37–38, §46). In addition, he asserts that the acquisition of private property must leave “enough and as good for others” (see §27 and §33).
Then Locke argues that property rights do not violate these moral rules in three different kinds of society. Hunter-gatherers are incapable of taking too much (§31). In agricultural societies, private property gives people incentives to improve the land as they can keep the benefits of their work. The greater productivity of the land is so vast that everyone benefits whether they have property or not (§32–44). Finally, commercial societies store value in something that cannot spoil or be used in any other way: money (§§45–51). So while each succeeding society is less equal than the one before, none run afoul of the limits of natural law.
It seems to me that you can find three different moral arguments for property rights in Locke:
A natural rights argument: people have natural rights to their bodies and so they acquire property rights when they labor on unowned things. Locke says, mysteriously, that they “mix” their labor with the things they come to own (§27)
A proto-utilitarian argument: God commands us to promote the good of mankind and property rights accomplish that goal by giving people an incentive to make natural resources more productive (§32).
A virtue argument: property rights go to the “industrious and rational” when you allocate them according to labor (§34). Since the industrious and rational deserve to have more than the slothful and foolish, the system of private property allocates resources in the appropriate way: it favors the virtuous over the vicious.
While Locke thinks they all amount to the same thing, they really have different implications. A utilitarian, for instance, would be willing to take away property from someone who labored if doing so would promote the overall good.