diligently examined;
those that rest on doubtful evidence should not be rejected, but noted
as uncertain, with the grounds of the judgment so formed. This last part
of the method, says Bacon, is very necessary, for facts often appear
incredible only because we are ill-informed, and they cease to seem
marvellous when our knowledge is further extended.

When this record of facts, this "natural history," is completed, an
attempt may then be made to discover, by a comparison of the various
facts, the cause of the phenomena. Here it is of the utmost importance
to bear in mind that all facts have not the same value. There are, as
Bacon points out, twenty-seven species of facts, and he concludes that
in any science where facts cannot be tested by experiment there can be
no conclusive evidence.

Thus it will be seen that Bacon's method was a system of specific rules.
He did not merely tell men to make observations and experiments; he
taught them how observations and experiments ought to be made.

As Bacon was the father of modern science, so Rene Descartes was the
father of modern philosophy. Born in 1596, and perplexed by the movement
of scepticism produced by the Renaissance, the French thinker
endeavoured to find some ground of certainty in the fact that he at
least knew of his own existence. Hence his famous saying: _Cogito, ergo
sum_--"I think, therefore I exist." Consciousness, said he, is the basis
of all knowledge. The process then is simple: examine your
consciousness, and its clear replies will be science. Hence the vital
portion of his system lies in this axiom: "All clear ideas are true."

The fallacy in his system can be briefly exposed. Consciousness is, no
doubt, the ultimate ground of certainty of existence for _me_. But
though I am conscious of all that passes within myself, I am not
conscious of what passes in anything not myself. All that I can possibly
know of anything not myself lies in its effects upon me. Any other ideas
I may have in regard to the outside world are founded only on
inferences, and directly I leave the ground of consciousness for the
region of inference my knowledge becomes questionable.

It was this defect in Cartesianism which Baruch Spinoza, the great
Jewish thinker of Amsterdam, set out to rectify. Spinoza asked himself:
What was the reality which lies beneath all appearance? We see
everywhere transformations perishable and perishing, yet there must be
something beneath which is i