Full Idea
In fact there is no difference between Protagoreanism and saying this: if you stick your finger under your eyes and make single things seem two, then they are two, just because they seem to be two.
Clarification
'Protagoreanism' is the relativist view that there is no truth, but only individual points of view
Gist of Idea
Relativists think if you poke your eye and see double, there must be two things
Source
comment on Protagoras (fragments/reports [c.441 BCE]) by Aristotle - Metaphysics 1063a06
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.331