Parmenides' premises in Protagoras' homo mensura

We show that Protagoras could prove his homo mensura thesis by means of two statements ascending to Parmenides. The first statement asserts that any complex (or whole) intentional object can be grasped only “all at once”, and not part by part. The second statement asserts that any intentional act is identical to its content. We can deduce from these two statements that any different intentional acts are always directed to different intentional objects. This is even more radical thesis than “relativism about truth”, which is traditionally ascribed to Protagoras: any proposition is true iff it belongs to the subject's system of believes. In conclusion, we show that not only the homo mensura thesis can be interpreted as a consequence of the above provisions of Parmenides, but certain Gorgias' statements can also be considered in a similar way.