Semiotics is a contemporary discipline that arose from the European structuralismof Saussure, Hjelmslev and Jakobson, and then (thanks to Eco) also receivedsome contributions from the thought of American philosopher Peirce. But, on adeeper analysis, it can be observed that it has its historical roots in the philosophicaltradition of classical antiquity. In this essay, the elements of continuity andthe differences between contemporary semiotics and this tradition are analyzed,starting from the most obvious, which concerns two different models for the conceptionof the sign (equivalence vs inference).