ABSTRACT
I shall be using the term “practice” in this book to mean an invention by human beings of a way of interacting whose elements depend on the agreement of the participants. Games such as football are examples of a practice. While there are, of course, physical features of the world including human beings that make the game possible, the rules that constitute the game, and hence the game itself, exist only insofar as some human beings agree to interact in accordance with them. Money is a human invention, and its use as a store of value and a medium of exchange constitutes a human practice in the same way. It can serve these functions only if human beings agree to attach that sort of value to certain things such as pieces of metal, bits of paper, cowrie shells and so on. Political constitutions such as the rule in the UK that a valid law requires the consent of both Houses of Parliament and the monarch are also examples of human practices. The facts in the world created by such practices are sometimes called social or institutional facts. They do not exist in the way the solar system exists. The facts about the solar system and such things exist independently of human beings and their beliefs. They are natural facts. Social or institutional facts exist only because of human beings’ inventive social schemes. They are, nevertheless, facts about the world.
