In the ordinary way, we all know very well what a contract is. It is a
mutual undertaking or promise by two or more parties to do or refrain
from doing something or another. Such promises may be made verbally,
by means of gestures, or expressed in writing, but they must be
expressed or else the contract is not merely null and void, but nonexistent.
There is no such thing as an inaudible and invisible contract.
To think otherwise is to mistake metaphorical for literal language. Yet
the history of political philosophy from the 17th century until the present
day has been dominated by the idea of a contract to which no persons
living or dead ever affixed a signature or so much as nodded
assent; a promise binding on the whole of civilised humankind, on
which are thought to rest the complementary edifices of civil society
and the state.