Rudolf Carnap: Truth Is Relative to Convention

“The conditions of the truth of sentences in a system need not be found outside the system [or convention], but must be provided within it.” — Rudolf Carnap

To put the following essay in context, let’s firstly quote two passages from Rudolf Carnap’s ‘Empiricism, Semantics, and Ontology’, which was published in 1950:

“If someone wishes to speak in his language about a new kind of entities, he must introduce a system of new ways of speaking, subject to new rules; we shall call this procedure the construction of a linguistic framework for the new entities in question.”

“To accept the thing world means nothing more than to accept a certain form of language, in other words, to accept rules for formulating statements and for testing, accepting, or rejecting them.”

The German philosopher (a logical positivist) Rudolf Carnap argued that truth is an “internal question”. That is, truth is internal to specific “conventions”.