The Opus Majus of Roger Bacon, Vol. 1 (English Translation)

and occasions of error at a farther remove from our weak power of sense perception.

Now there are four chief obstacles in grasping truth, which hinder every man, however learned, and scarcely allow any one to win a clear title to learning, namely: submission to faulty and unworthy authority, influence of custom, popular prejudice, and concealment of our own ignorance accompanied by an ostentatious display of our knowledge. Every man is entangled in these difficulties, every rank is beset. For people without distinction draw the same conclusion from three arguments, than which none could be worse, namely: for this the authority of our predecessors is adduced, this is the custom, this is the common belief; hence it is correct. But an opposite conclusion and a far better one should be drawn from the premises, as I shall abundantly show by authority, experience, and reason. Should, however, these three errors be refuted by the convincing force of reason, the fourth is always ready and on everyone’s lips for the excuse of his own ignorance; and although he has no knowledge worthy of the name, he may yet shamelessly magnify it, so that at least to the wretched satisfaction of his own folly he suppresses and evades the truth. Moreover, from these deadly banes come all the evils of the human race; for the most useful, the greatest, and most beautiful lessons of knowledge, as well as the secrets of all science and art, are unknown. But, still worse, men blinded in the fog of these four errors do not perceive their own ignorance, but with every precaution cloak and defend it so as not to find a remedy; and worst of all, although they are in the densest shadows of error, they think that they are in the full light of truth. For these reasons they reckon that truths most firmly established are at the extreme limits of falsehood, that our greatest blessings are of no moment, and our chief interests possess neither weight nor value. On the contrary, they proclaim what is most false, praise what is worst, extol what is most vile, blind to every gleam of wisdom and scorning what they can obtain with great ease. In the excess of their folly they expend their utmost efforts, consume much time, and pour out large expenditures on matters of little or no use and of no merit in the judgment of a wise man. Hence it is necessary that the violence and banefulness of these four causes of all evils should be recognized in the beginning and re-