t gives no satisfaction or certainty to the mind, which can
only be convinced by immediate inspection or intuition. Now this is what
experience gives. But experience is of two sorts, external and internal;
the first is that usually called experiment, but it can give no complete
knowledge even of corporeal things, much less of spiritual. On the other
hand, in inner experience the mind is illuminated by the divine truth, and
of this supernatural enlightenment there are seven grades.

Experimental science, which in the _Opus Tertium_ (p. 46) is distinguished
from the speculative sciences and the operative arts in a way that forcibly
reminds us of Francis Bacon, is said to have three great prerogatives over
all other sciences:--(1) It verifies their conclusions by direct
experiment; (2) It discovers truths which they could never reach; (3) It
investigates the secrets of nature, and opens to us a knowledge of past and
future. As an instance of his method, Bacon gives an investigation into the
nature and cause of the rainbow, which is really a very fine specimen of
inductive research.

The seventh part of the _Opus Majus_ (_De Morali Philosophia_), not given
in Jebb's edition, is noticed at considerable length in the _Opus Tertium_
(cap. xiv.). Extracts from it are given by Charles (pp. 339-348).

As has been seen, Bacon had no sooner finished this elaborate work than he
began to prepare a summary to be sent along with it. Of this summary, or
_Opus Minus_, part has come down and is published in Brewer's _Op. Ined._
(313-389), from what appears to be the only MS. The work was intended to
contain an abstract of the _Opus Majus_, an account of the principal vices
of theology, and treatises on speculative and practical alchemy. At the
same time, or immediately after, Bacon began a third work as a preamble to
the other two, giving their general scope and aim, but supplementing them
in many points. The part of this work, generally called _Opus Tertium_, is
printed by Brewer (pp. 1-310), who considers it to be a complete treatise.
Charles, however, has given good grounds for supposing that it is merely a
preface, and that the work went on to discuss grammar, logic (which Bacon
thought of little service, as reasoning was innate), mathematics, general
physics, metaphysics and moral philosophy. He founds his argument mainly on
passages in the _Communia Naturalium_, which indeed prove distinctly that
it was sent to Clement, and cannot,