Any one who in discussion relies upon authority uses, not his understanding, but rather his memory. Good culture is born of a good disposition; and s… - Leonardo da Vinci

Anyone who in discussion quotes authority uses his memory rather than his intellect.

Those who are in love with practice without knowledge are like the sailor who gets into a ship without rudder or compass and who never can be certain whether he is going. Practice must always be founded on sound theory, and to this Perspective is the guide and the gateway; and without this nothing can be done well in the matter of drawing.

Things severed shall be united and shall acquire of themselves such virtue that they shall restore to men their lost memory:—That is the papyrus sheets, which are formed out of several strips and preserve the memory of the thoughts and deeds of men.

The city will gain beauty worthy of its name and to you it will be useful by its revenues, and the eternal fame of its aggrandizement.