I'm not surprised it's not clear - there are many incentives to deliberately confuse yourself about property rights. Anything less than a full and ironclad definition will be challenged. Indeed even the ironclad definition will be challenged, but not coherently.
You control yourself. Actually, whatever controls your body is you.
It works like this. Your arms can wave about. Something controls that waving. That thing also controls your mind and vocal cords, which means that the only thing we can interact with (at least with current tech) is your body's controller.
This is typically what we mean when we say 'you' - it is the thing that controls your body. So, you control yourself, and this is incontrovertible.
There are two parts to the next argument. First, that property rights are inevitable. Second, once they exist, property rights can't be contravened by anyone without logical contradiction. My apologies for the clunky wording. The underlying concepts are much more elegant; I simply haven't found the good, simple, straightforward way to express them.
Aliens will have property rights. All finite living beings (all life has goals, all things that can be assigned goals are living) need to control their environment, or they perish. They need to be able to achieve their goals, or they become non-living. This control is an extension of self-control.
As a result, all life will expect to be able to control their environment. If they did not, they would not waste the energy to try - and they would perish, unable to reach or even strive for goals. Conversely, if they did try but could not expect to control their environment, they would run out of energy and perish. This expectation of control is inevitable for anything that lives.
Because I am a living thing I expect that I can control my environment.
Because you are also a living thing, the situation is symmetrical. Especially since we are, for all intents and purposes, the identical type of thing - human. (Some tiny differences with gender or birth defects I am ignoring for the moment.)
We call this fact ownership - the control of something leads directly from the expectation of control, which is ownership, and vice-versa; ownership leads from control. We cannot both reasonably expect to control a single thing at the same time. (Without fusing our mind/controller so that we are a single entity.)
Since control inevitably implies ownership, I have ownership of my body. I can claim ownership of the environment by exerting my bodily control to control my environment. Having done so, if a person attempts violence, such as theft, upon my property, they also expect to own this part of the environment. However, logically, this is impossible.
I own, for instance, my wallet because I reasonably expect to control it. If a thief also reasonably expects to control it, the thief also owns it. (Assume the theft will be successful, as the thief must, or they would not attempt the theft.) We both own the wallet. This is immediately contradictory; but we cannot both control the wallet, and we cannot both reasonably expect to control the wallet. As a result, if the thief can reasonably expect to control the wallet, nobody owns the wallet. Which means the thief doesn't own the wallet. Which means they don't expect to own it. Which means they're not going to be a thief, and we see the contradiction again; to violate property rights leads to logical contradictions. To attempt theft is to violate the very reasons you are attempting theft. Theft is inherently hypocritical.
Again, if we did not expect to control something - if ownership or property does not exist - then we would not try to control it at all.
Indeed, all immoral behavior is, as I can verify, hypocritical. All evil is hypocritical; hypocrisy is the only evil. I can verify it not just logically, but empirically; nearly everything called immoral is hypocritical in this way.
- You must be able to reasonably expect to control your environment (as all living things must, but this is irrelevant - you must, this is a fact.)
- Two agents cannot both control one object at a single time.
- Only one agent can reasonably expect to control one object at a single time.
- We call this ownership.
- If a second agent attempts to violate (they must use violence) the ownership of a first agent, the second agent must reasonably expect to control the object.
- Theft (less obviously, all violence) requires that two entities own an object at one time.
- Theft is logically contradictory, by (2.)
- You cannot commit theft without hypocrisy - without contradicting a concept you are using in your reasons for theft.
So, as I've heard before, someone will say, though with less sophistication and clarity, "But that only means that ownership is simply an invalid concept!" This cannot be the case; a reasonable expectation of control is necessary for you to even to type out the objection. You must own your body, your keyboard, and rent the internet, at least long enough for it to get to me.
Again, if you did not reasonably expect to control your keyboard (you didn't own it) you wouldn't try to type, and I would never get your message.
(Renting: A time-delimited agreement of reasonable expectation of control, usually with physical limitations placed by the previous/subsequent owner, also usually with various clauses that immediately transfer back the reasonable expectation of control if the physical limitations are violated. Essentially borrowing for money - the real owner agrees to exerts their right to not control the borrowed object as long as you keep exerting your right to hand over the cash.)
There was at least one benefit to me from being challenged. I thought that ownership inevitably implied control, which is only almost true. Indeed, if you are not mistaken, ownership and control are always the same. However, because ownership is only a subjective expectation of control, not actual control itself, in physical terms they don't always coincide. Also, typing that last sentence inspired a whole new post on subjectivity, which I'll complete in the hazy future.
To conclude, we see again that there is but a short hop from property rights to universal ethics.