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them, that is in whose mind an interpreting sign is determined.
In this case, we may call the sign-maker the graphist and the other the interpreter.
The interpreter may be the graphist's future self.
Thse two persons in order to have any intercourse must go upon a basis of common past experience, well understood between them.
When one says to the other 'It is cold', the other knows that he does not mean that it was cold in feel and during the glacial period or that it was cold in the Caputa of Gullivers travels.
The sum total of what they one understand one another to be talking about, is what logicians call the universe of discourse.
De Morgan introduced the term in November 6, 1846.
Exact logic dates from the day.
There are certain truth which they well understand one another hold as indubitable concerning that universe.