[JumpCrisscross]

> It's an abstract idea that we can have more or less of, not a raw physical quantity that can utilize directly, like space or fuel

Uh, intellectual property. Also land ownership is an abstract idea. (Ownership per se is an abstract idea.)

[fluoridation]

Land is obviously a finite resource. I don't know what point you're trying to make with regards to intellectual property.

[JumpCrisscross]

> don't know what point you're trying to make with regards to intellectual property

Stocks. Bonds. Money, for that matter. These are all "abstract idea[s] that we can have more or less of, not a raw physical quantity." We can still characterise them as rival and/or excludable.