摘要：In the Tractatus Logico-Philosophicus the identity signal is excluded from any meaningful language use, because expressions such as “a = a” and “a = b” cannot be elementary and necessary propositions at the same time. Hence, the identity is used as a operation. That use does not intended to be be meaningful, but only to indicate the intersubstitutable nature of the signs involved.
关键词：identity;operation;meaning;elementary proposition.;Identidade;operação;significado;proposição elementar
