I intend to discuss some selected topics of Ajdukiewicz's "Language and Meaning'¹ and Wittgenstein's The Blue Book,² both works dating from 1934. Though thoroughly independent and rooted in different methods of philosophising, they are worth comparing as being similar in accounting for the role of sentences in the specification of meaning. In analysing the structure of a meaning-rule and a criterion I particularly focus on the postulate of the intersubjectivity of meaning — undoubtedly a pillar of the semantic programmes Ajdukiewicz and Wittgenstein propose. First, I inquire into the security measures Ajdukiewicz takes to make his empirical meaning-rule intersubjective. Then, I compare the paradigm of the empirical meaning-rule with Wittgenstein's defining criterion to judge its intersubjectivity. I conclude that Ajdukiewicz's measures are insufficient, at least if confronted with Wittgenstein's extreme requirements for intersubjectivity.