I mean that the function of money is not a physical, distinct, locatable object you can point to and say "look, there it is," like you might do if you see someone using an axe or driving a car. The function is to embody a social relation, so to point at what money "does," you need to point at a social situation involving more than two people. But a dry description of the situation isn't enough, you need to include subjective understanding of the meaning of various items and actions in the situation to appreciate what money "does".What do you mean by "not a thing"? Seriously if you haven't read the book I linked in post 2 you probably want to if this stuff interests you.
I think I will check out that book, it looks to be very interesting.