te as impatient as the scientists of our time
with the constant putting forward of Aristotle as if that settled a
scientific question. Roger Bacon wanted the Pope to forbid the study of
Aristotle because his works were leading men astray from the study of
science, his authority being looked upon as so great that men did not
think for themselves but accepted his assertions. Smaller men are always
prone to do this, and indeed it constitutes one of the difficulties in
the way of advance in scientific knowledge at all times, as Roger Bacon
himself pointed out.

These are the sort of expressions that are to be expected from Friar
Bacon from what we know of other parts of his work. His "Opus Tertium"
was written at the request of Pope Clement IV, because the Pope had
heard many interesting accounts of what the great thirteenth-century
teacher and experimenter was doing at the University of Oxford, and
wished to learn for himself the details of his work. Bacon starts out
with the principle that there are four grounds of human ignorance. These
are, "first, trust in inadequate authority; second, that force of custom
which leads men to accept without properly questioning what has been
accepted before their time; third, the placing of confidence in the
assertions of the inexperienced; and fourth, the hiding of one's own
ignorance behind the parade of superficial knowledge, so that we are
afraid to say I do not know." Professor Henry Morley, a careful student
of Bacon's writings, said with regard to these expressions of Bacon:

No part of that ground has yet been cut away from beneath the
feet of students, although six centuries have passed. We still
make sheep-walks of second, third and fourth, and fiftieth
hand references to authority; still we are the slaves of
habit, still we are found following too frequently the
untaught crowd, still we flinch from the righteous and
wholesome phrase "I do not know" and acquiesce actively in the
opinion of others that we know what we appear to know.

In his "Opus Majus" Bacon had previously given abundant evidence of his
respect for the experimental method. There is a section of this work
which bears the title "Scientia Experimentalis." In this Bacon affirms
that "without experiment nothing can be adequately known. An argument
may prove the correctness of a theory, but does not give the certitude
necessary to remove all doubt, nor will the mind repose