THE AGE OF EXPANSION 323

move doubt and cause the mind to rest in the conscious posses-
sion of truth, unless the truth is discovered by way of experience,
e.g., if any man who had seen fire were to prove by satisfactory
argument that fire burns and destroys things, the hearer's mind
would not rest satisfied, nor would it avoid fire ; until by put-
ting his hand or some combustible thing into it, he proved by
actual experiment what the argument laid down ; but after the
experiment had been made, his mind receives certainty, and rests
in the possession of truth which could not be given by argument,
but only by experience.

Roger Bacon, as Westaway says, stands out for all time
as the successful pioneer of experimental investigation. In
the succeeding centuries (1301-1600) there were creative
geniuses in every walk of life. The spirit of Roger Bacon
and Columbus was abroad, and the enlightenment of Dante
(1265-1321) and Petrarch (1304-74) appeared to inspire
everybody. The versatility of Michael Angelo (1475-1564)
and Leonardo da Vinci (1452-1519) is admired even to-day.
Copernicus the Pole (1473-1543), Tycho Brahe the Dane
(1546-1601), Kepler the German (1571-1630), and Galileo
the Italian (1564-1642),—all astronomers of the greatest re-
pute, extended the vision of humanity to worlds beyond the
terrestrial. The invention or introduction of printing with
moveable types (first used by the Chinese) had even more
momentous consequences than that of the mariner's compass.
Professor Will Durant has rightly described this as the great-
est invention, after writing, in the history of cur race.1 The
pioneers in Europe in this direction were Guttenberg (Ger-
many) and Caxton (England). The Chinese had discovered
the art of manufacturing paper out of silk; the Arabs and
Europeans substituted linen for this. The simultaneous con-

1. Read further details in The Story of Civilization, II, p. 727-
31; and for an account of scientific progress, Westaway, The
Endless Quest, pp. 102 ff.