Property as matter is fixed in time and space. It can shift in time and space, but it occupies space such that its presence in one place precludes its presence elsewhere. (Exceptions are when something is considered as a whole but can be split up, like air and water).
Ownership of an item means that it is your possession or under your oversight. You get to determine how it is used (within the confines of legality).
The limitation of locality and the fact of ownership means that a person can take an item, or place a claim to an item that is not his. Such behaviour is considered theft. It would include taking a computer from work, tomatoes out of your neighbour's garden, or shifting a boundary marker.
Contrast this to what is referred to as intellectual property. I have suggested we use an alternative term to prevent equivocation on the word property; such as "concept", "conceptualisation", "idea", "abstraction", or perhaps a Greek or Latin derived neologism. I will use concept in this post.
Concepts are information. Information does not have qualities of matter. It does not consist of length (in the usual sense), mass, time, current, or temperature. Thus it is non-material. It is still a real entity, just not a material one.
Therefore concepts are not restricted by the laws of physics. Concepts can be duplicated. Concepts can be lost or destroyed. Greek fire is a concept that has been lost. There is no conservation of matter or energy law that corresponds to concepts.
This means that concepts cannot be stolen in the way that property can be stolen. If you give someone else your concept you still have it. Because you still have your concept you cannot say that it has been removed from you. You can still use your concept. The difference is that now someone else has access to the concept and can use it as well.
I used the example of an axe. If someone steals your axe then they have it and you cannot use it. But if someone sees your axe and makes his own then he has not stolen your axe, you still have it. He now also has an axe because he has used your concept: the idea of attaching a splitting wedge to a stick.
Concepts can be mildly to very complicated. Complexity does not correspond directly to usefulness. And less complex concepts are not always obvious before the fact. A less complex solution to a problem may replace a more complex solution because of simplicity and cost.
The distinction between property as matter and concepts as information is foundational. One that must be apprehended before discussion about what copyright might entail. A rule of thumb in distinguishing between property and concepts: If you give something away and no longer have it, it is material; if you give it away and still have it, then it is information. As George Bernard Shaw said,
If you have an apple and I have an apple and we exchange apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas.