Book VI · 35
Dost thou not see how the handicrafts-men accommodate themselves up to a certain point to those who are not skilled in their craft—nevertheless they cling to the reason [the principles] of their art, and do not endure to depart from it? Is it not strange if the architect and the physician shall have more respect to the reason [the principles] of their own arts than man to his own reason, which is common to him and the gods?
Marcus Aurelius, Meditations VI.35. Translated by George Long (1862). The Stoic Library.