Persist in your investigation

I observed too his habit of careful inquiry in all matters of deliberation, and his persistency, and that he never stopped his investigation through being satisfied with appearances which first present themselves.  Marcus Aurelius observing his father, the emperor Antoninus Pius.  Meditations. Book 1.  

Converted to a principle of living:  Perform careful inquiry in all matters of deliberation.  Persist and never stop your investigation through being satisfied with appearances which first present themselves.

Image: Archimedes by Luca Giordano, 1650-53, now in The Gemäldegalerie in Berlin, Germany, courtesy of Wikimedia Commons contributor anagoria.