"The divisions we make are contractual. Where we draw the dividing line is simply a matter of convention within a given society or group. Divisions that we believe are true are not really an internal feature of reality. They are external. We add them, from the outside.
Let us take an example. How big is the sun? In other words, where does the sun end, and what does not the sun begin? We used to say that the sun is made of visible fire. The moment you cross the visible fire, you go to something that is no longer the sun, but an external space to it.
But you could also say that the sun is made of heat. It makes sense, doesn't it? Then, following such thinking, one would have to conclude that the Earth is contained within the Sun, and the boundary is somewhere further in space and begins where the heat ends.
We could, however, say that the sun is made of light. On this assu