But for the purpose of his tetralogies he reckoned them only as thirty-six — nine groups.
But they still continued to look for Plato in the nine Tetralogies of Thrasyllus, in each and all of them.
This remark would seem to apply more precisely to the arrangement of the dialogues into trilogies and tetralogies.
His word φιλοσόφως belongs very justly to the logical distribution of Thrasyllus, apart from the tetralogies.
One of these distributions was into Tetralogies, or groups of four each.