"And when he reaches early adolescence he must become possessed with an ardent love for truth, like one inspired, neither day nor night may he cease to urge and strain himself in order to learn thoroughly all that has been said by the most illustrious of the Ancients. And when he has learnt this, then for a prolonged period he must test and prove it, observe what part is in agreement, and what in disagreement with obvious facts; thus he will choose this and turn away from that. To such a person my hope has been that my treatise would prove of the very greatest assistance. Still, such people may be expected to be quite few in number, while, as for the others, this book will be as superfluous to them as a tale told to an ass."
--Galen, On the natural faculties, III, 10.
[Translation by
Arthur John Brock, M. D. The Loeb Classical Library P. 279/281.]