Abstract
The article deals with the ancient rhetoric formula of the parts of speech in order to demonstrate possible inefficacy of rhetorical criticism as a interpretation method. First, it reminds about Cole's and Schiappa's propositions to date the beginning of the four parts of speech theory to 1st half of the 4th century BC, that is to the time when model-speeches had either already been written or only were being developed.
Therefore a number of them were not subdivided to the traditional four parts. However, emulating those speeches was a more important way of later rhetorical education and production in comparison with only following some theoretical rules.
Further, it reports the debates of later rhetoricians about whether the rhetorical rules should always be observed or whether their application is optional depending on actual real conditions. The explanation of the parts of speech formula indicates that the interpretation method based on rhetorical criticism should confront the question of what could actually be regarded as the decisive rhetorical theory.