losophy for the benefit of the Pope. He therefore produced in a very short time three books, Opus
Majus, Opus Minus, and Opus Tertium. These seem to have produced a good impression, and in
1268 he was allowed to return to Oxford, from which he had been removed to a sort of
imprisonment in Paris. However, nothing could teach him caution. He made a practice of
contemptuous criticism of all the most learned of his contemporaries; in particular, he maintained
that the translators from Greek and Arabic were grossly incompetent. In 1271, he wrote a book
called Compendium Studii Philosophiae, in which he attacked clerical ignorance. This did nothing
to add to his popularity among his colleagues, and in 1778 his books were condemned by the
General of the order, and he was put in prison for fourteen years. In 1292 he was liberated, but
died not long afterwards.
He was encyclopædic in his learning, but not systematic. Unlike most philosophers of the time,
he valued experiment highly, and illustrated its importance by the theory of the rainbow. He wrote
well on geography; Columbus read this part of his work, and was influenced by it. He was a good
mathematician; he quotes the sixth and ninth books of Euclid. He treated of perspective, following
Arabic sources. Logic he thought a useless study; alchemy, on the other hand, he valued enough to
write on it.
To give an idea of his scope and method, I will summarize some parts of the Opus Majus.
There are, he says, four causes of ignorance: First, the example of frail and unsuitable authority.
(The work being written for the Pope, he is careful to say that this does not include the Church.)
Second, the influence of custom. Third, the opinion of the unlearned crowd. (This, one gathers,
includes all his contemporaries except himself.) Fourth, the concealment of one's ignorance in a
display of apparent wisdom. From these four plagues, of which the fourth is the worst, spring all
human evils.
In supporting an opinion, it is a mistake to argue from the wisdom of our ancestors, or from
custom, or from common belief. In support of his view he quotes Seneca, Cicero, Avicenna,
Averroes, Adelard of Bath, Saint Jerome, and Saint John Chrysostom. These authorities, he seems
to think, suffice to prove that one should not respect authority.
His respect for Aristotle is great, but not unbounded. "Only Aristotle, together with his followers,
has been called philosopher in the