I came across an argument that I believe to be invalid:

Ownership is defined as the ability to exclude others. "Everyone owns land" becomes "everyone has the ability to exclude others from land."

I believe it's a contradiction to say "everyone" can exclude "others" because how are there "others" outside of the set of "everyone". When I pointed this out, the argument was "rephrased" to be more "theoretical" (not actual theory, but logic).

Ownership is defined as the right to exclude others. "Everyone owns land" becomes "everyone has the right to exclude others from land"...theoretically.

Still, even ignoring reality, it makes no sense to there are "others" outside of the set containing "everyone". Even if you used all possible humans (a la Schopenhaur's "all possible worlds"), you'd need to apply the expanded set to BOTH "everyone" AND "others", thus not making any headway. You can't just apply a set expansion to "others" and not to "everyone" as well, right?

Keep in mind, we're assuming the premise of the argument and just looking at the sequitur.

  • 1
    "Everyone has the ability to exclude others" means "for each person, that person has the ability to exclude others [=other than that person]", so there's no contradiction. "Others" does not refer to those other than everyone.
    – E...
    Feb 21, 2019 at 7:09
  • 1
    "set theory" ???? Feb 21, 2019 at 7:17
  • You are misinterpreting the ststement. Others is part of everyone.. not outside it. almost all land is owned, even roads.. but a lot of it is designated as common land. However.. nobody would buy land if it didnt confer certain rights, even if those rights cant be executed until some unspecified future time. People in the UK buy woodland with no building permits... because they know.. perhaps it will make their grandchildren rich.
    – Richard
    Feb 21, 2019 at 11:06
  • Where is ownership defined in such a convoluted way? I never thought of thinking of owning a sweater as my right to exclude others from wearing it.
    – Joachim
    Feb 21, 2019 at 13:08
  • This seems like a legal question, the way that it is presented here. A more philosophical approach might question the ethics of ownership of land, etc.
    – Bread
    Feb 21, 2019 at 22:41

2 Answers 2


'Ownership is defined as the right to exclude others'

I'm reminded of the English legal theorist, Blackstone's definition : ownership is 'that sole and despotic dominion which one man (sic) exercises over the external things of the world, in total exclusion of any other individual in the universe' (2 William Blackstone, Commentaries *2.)

Ownership as control of use

I prefer a different approach. Sole control over an asset, with the right to exclude all others from its use, does not seem to me the most fruitful or most realistic route to understanding the nature of property. Ownership seems to me esssentially tied to the control of some aspect of a particular thing's use. More specifically :

a property right should be understood as a right conferring some measure of legal authority to determine how a particular thing may be used — authority that comes at the expense of all others asserting authority over the use of the thing. (James Y. Stern, 'Property's Constitution', California Law Review, Vol. 101, No. 2 (April 2013), pp. 277-326: 283.)

the law of property tells us who is in charge and to what extent as well as who has authority to decide how the thing will be used when disputes over use arise. The basic structure of property law is something like what parents do when they sew nametags into their children's clothes before sending them to summer camp. Property law affixes a sort of invisible tag to every object in the world, naming the person authorized to decide how to use the object. There need not be a single name on the tag—B might be empowered to make most decisions subject to an exception allowing A to decide some particular question or to take over at some particular point in time. The permutations can be exceedingly complex. But it is important to recognize the sort of conflicts that the law of property addresses—conflicts arising from competing claims to control some particular resource—and the way it addresses them. Property law tells us who gets to decide how a given resource may be used. (Stern: 294.)

Limits to control of use

This passage presents a more complex and to my mind more realistic account of the general nature of property rights and hence of ownership. Something may be my property, therefore something I own, but the extent to which I can determine how a particular thing (my property) can be used may be limited. What's more, I am unlikely in any system of property rights to have the sole, and in some cases any, authority in a dispute over how my property will be used. I may own a strip of land but it may include a public right of way; and I will be unlikely to have the authority, legal and I should add moral, to use my land as I wish if I obstruct the needful public take-over of the land in a humanitarian catastrophe.

I'd add that ownership may not be all or nothing. I may have the sole right to determine most but not all uses of a thing. I have the sole right to determine the use of a litre of sulphuric acid in cleaning my drains but no right to serve it to a guest as a drink.

Exclusion not the key

The model on which ownership entails an owner with sole control over an asset, with the right to exclude all others from its use, is not adequate in my view to the concept of property.


I think that there is some ambiguity here. What do you mean by “Everyone owns land.”? From context, I believe that you mean that “There exists some land that everyone (as a single entity) owns.”. However, without context, I would have interpreted it as “For each person, there exists some land which that person owns.”.

From what I understand, your main qualm is with the notion of understanding what “others” refers to when using the concept of “everyone” to determine it.

One way to think of this is to think of those who own land as sets of people. Then we may think of “everyone” as a set containing each person. And for any given any set of people, if we label it “entity A”, we may define the “others of entity A” as “everyone” setminus “entity A”. In this viewpoint, the “others of everyone” would be the empty set.

Logically: For each person, that person is part of “everyone”. For each person, that person is in “everyone” implies that that person is not a part of “others of everyone”. Therefore for each person, that person is not in “others of everyone”.

There is no contradiction here. A contradiction is a statement of the form “p and not p” where p is a statement. What would be a contradiction is “there is a person who is in the ‘others of everyone’”.

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