letter of Roger Bacon contains every idea that the modern
scientists contend for as significant in education. It counsels
observation, not theory, and says very plainly what he thinks of much
talk without a basis of observation. It commends a mastery in
experiment as the most important thing for science. It suggests, of
course, by implication at least, that a man should know all sciences
and all applications of them; but surely no one will object to this
medieval friar commending as great a breadth of mental development as
possible, as the ideal of an educated man, and especially with regard
to the experimental sciences. Finally, it has the surprising phrase,
that Peregrinus pursues knowledge for its own sake. Friar Bacon
evidently would have sympathized very heartily with Faraday, who at
the beginning of the nineteenth century wanted to get out of trade and
into science, because he thought it unworthy of man to spend all his
life accumulating money, and considered that the only proper aim in
life is to add to knowledge. He would have been in cordial accord with
Pasteur, at the end of the century, who told the Empress Eugenie, when
she asked him if he would not exploit his discoveries in fermentation
for the purpose of building up a great {290} brewing industry in
France, that he thought it unworthy of a French scientist to devote
himself to a mere money-making industry.

For a man of the modern time, perhaps the most interesting expression
that ever fell from Roger Bacon's lips is his famous proclamation of
the reasons why men do not obtain genuine knowledge more rapidly than
would seem ought to be the case, from the care and time and amount of
work which they have devoted to its cultivation. This expression
occurs in Bacon's Opus Tertium, which, it may be recalled, the
Franciscan friar wrote at the command of Pope Clement, because the
Pope had heard many interesting accounts of all that 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. Friar Bacon starts out with the principle that there are
four grounds of human ignorance.

"These are: first, trust in adequate authority; second, that force of
custom which leads men to accept too unquestioningly what has been
accepted before their time; third, the placing of confidence in the
opinion of the inexperienced; and fourth, the hiding of one's own
ignorance with the parade