Roger Bacon

"I have labored much in sciences and languages, and I have up to now devoted forty years after I first learned the Alphabetum; and I was always studious. Apart from two of these forty years I was alway…"

"And because this Experimental Science is wholly ignored by the general run of students, for that reason I can not convince people of its utility unless I show at the same time its excellence and its p…"

"Mathematics is the gate and key of the sciences. ... Neglect of mathematics works injury to all knowledge, since he who is ignorant of it cannot know the other sciences or the things of this world. An…"

"For the things of this world cannot be made known without a knowledge of mathematics. For this is an assured fact in regard to celestial things, since two important sciences of mathematics treat of th…"

"There are in fact four very significant stumbling blocks in the way of grasping the truth, which hinder every man however learned, and scarcely allow anyone to win a clear title to wisdom, namely, the…"

"Mix together saltpetre, luru vopo vir con utriet , and sulphur, and you will make thunder and lightning, if you know the method of mixing them."

"If in other sciences we should arrive at certainty without doubt and truth without error, it behooves us to place the foundations of knowledge in mathematics..."

"Argument is conclusive... but... it does not remove doubt, so that the mind may never rest in the sure knowledge of the truth, unless it finds it by the method of experiment. For if any man who never …"