possible in
domains where now only conjecture and probability exist. It will enable
us to establish on a firm and secure foundation the _Laws or Principles
of every department of the Universe of Matter and of Mind_, and to
penetrate the Phenomena of all realms to an extent now scarcely
imagined. It will furnish us the 'Criterion of Truth' so long sought
after--a ground of intellectual agreement in all the concerns of life,
so far as this is essential, similar to that which we now have in
Mathematics, where difference of opinion is impossible because _proof is
of a nature to be alike convincing to all_.

But, as in Mathematics a limit is reached, beyond which the finite
character of our intelligence does not permit us to _apply_ the Laws
which we are well assured still prevail, so there is an outlying circle
of practical activity which no Science can compass. The various tints of
the autumn forest are probably the results of Mathematical arrangements
of particles; but to how great an extent we shall be able to discover
what precise arrangement produces a given shade of color, is doubtful.
Some delicate varieties, at least, will always be beyond our definite
apprehension. Whether we shall dine at one hour or another, whether we
will wear gray or black, and innumerable other questions of specialty,
do not come within the range of Scientific solution, and never can. So
that when every domain of human concern is solidly established on a
basis of Exact Science, there will still remain a field of indefinite
extent, in which the Intuitive application of eternal Principles will
furnish an unlimited activity for the Practical, AEsthetic, Imaginative,
Idealistic, Artistic, and Religious faculties of Mankind.

The task which Mr. Buckle set himself to accomplish was, in a marked
sense, original and peculiar. Although several systematic attempts had
been made in Europe, prior to his time, to investigate the history of
man according to those exhaustive methods which in other branches of
Knowledge have proved successful, and by which alone empirical
observations can be raised to scientific truths, the imperfect state of
the Physical Sciences necessarily rendered the execution of such an
undertaking extremely defective. It was not, indeed, until the vast mass
of Facts which make up the body of the various Sciences had been
included within appropriate formulae, and until the elaborate
Classification of Auguste Comte had separated tha