To begin is the most important part of any quest and by far the most courageous.
... for this discovery of yours will create forgetfulness in the learners' souls, because they will not use their memories; they will trust to the external written characters and not remember of themselves.
Seek truth while you are young, for if you do not, it will later escape your grasp
The wisest have the most authority.
The knowledge of which geometry aims is the knowledge of the eternal.
As the builders say, the larger stones do not lie well without the lesser.