Roger Bacon - Collected Quotes

"All science requires mathematics […] the knowledge of mathematical things is almost innate in us […] this is the easiest of sciences. A fact which is obvious in that no one’s brain rejects it. For laymen and people who are utterly illiterate know how to count and reckon.” (Roger Bacon, "Opus Majus”, 1267)

"For the things of this world cannot be made known without a knowledge of mathematics.” (Roger Bacon, "Opus Majus”, 1267)

"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.” (Roger Bacon, "Opus Majus", 1267)

"Mathematics is the door and key to the sciences.” (Roger Bacon, "Opus Majus", 1267)

"Reasoning draws a conclusion and makes us grant the conclusion, but does not make the conclusion certain, nor does it remove doubt so that the mind may rest on the intuition of truth, unless the mind discovers it by the path of experience.” (Roger Bacon, "Opus Majus", 1267)

"There are four great sciences, without which the other sciences cannot be known nor a knowledge of things secured […] Of these sciences the gate and key is mathematics […] He who is ignorant of this [mathematics] cannot know the other sciences nor the affairs of this world.” (Roger Bacon, "Opus Majus", 1267)

"There are two modes of acquiring knowledge, namely, by reasoning and experience. Reasoning draws a conclusion and makes us grant the conclusion, but does not make the conclusion certain, nor does it remove doubt so that the mind may rest on the intuition of truth unless the mind discovers it by the path of experience.” (Roger Bacon, "Opus Majus", 1267)

"Without experience nothing can be sufficiently known. For there are two modes of acquiring knowledge, namely, by reasoning and by experience. Reasoning draws a conclusion and makes us grant the conclusion, but does not make the conclusion certain [...] unless the mind discovers it by the method of experience." (Roger Bacon, "Opus Majus", 1267)

"All sciences are connected; they lend each other material aid as parts of one great whole, each doing its own work, not for itself alone, but for the other parts; as the eye guides the body and the foot sustains it and leads it from place to place.” (Roger Bacon, "Opus Tertium”, [1266–1268])

"Neglect of mathematics works injury to all knowledge, since one who is ignorant of it cannot know the other sciences of the things of this world. And what is worst, those who are thus ignorant are unable to perceive their own ignorance and so do not seek a remedy." (Roger Bacon)

"The strongest arguments prove nothing so long as the conclusions are not verified by experience. Experimental science is the queen of sciences and the goal of all speculation." (Roger Bacon)