  Radical conventionalism is an epistemological theory developed by Ajdukiewicz in the early 1930s. It is based on a conception of language and meaning. The concept of meaning is taken as a primitive. Now, the meaning of expressions in a language L induces the rules for accepting its sentences. Ajdukiewicz lists three kinds of meaning-rules (or sense-rules): (a) axiomatic (they demand the unconditional acceptance of sentences, for example, “A is A”; (b) deductive (they demand the acceptance of a sentence relatively to the prior acceptance of other sentences, for example, ¬A follows from A → B and ¬B), (c) empirical (they demand the acceptance of a sentence in a definite empirical situation, for example “it is raining” when it rains).