itself, considered not as to its
results, the truths which it ascertains, but as to the processes by
which the mind attains them, the marks by which it recognises them, and
the co-ordinating and methodizing of them with a view to the greatest
clearness of conception and the fullest and readiest availibility for
use: in one word, the logic of the science. M. Comte has accomplished
this for the first five of the fundamental sciences, with a success
which can hardly be too much admired. We never reopen even the least
admirable part of this survey, the volume on chemistry and biology
(which was behind the actual state of those sciences when first written,
and is far in the rear of them now), without a renewed sense of the
great reach of its speculations, and a conviction that the way to a
complete rationalizing of those sciences, still very imperfectly
conceived by most who cultivate them, has been shown nowhere so
successfully as there.

Yet, for a correct appreciation of this great philosophical achievement,
we ought to take account of what has not been accomplished, as well as
of what has. Some of the chief deficiencies and infirmities of M.
Comte's system of thought will be found, as is usually the case, in
close connexion with its greatest successes.

The philosophy of Science consists of two principal parts; the methods
of investigation, and the requisites of proof. The one points out the
roads by which the human intellect arrives at conclusions, the other the
mode of testing their evidence. The former if complete would be an
Organon of Discovery, the latter of Proof. It is to the first of these
that M. Comte principally confines himself, and he treats it with a
degree of perfection hitherto unrivalled. Nowhere is there anything
comparable, in its kind, to his survey of the resources which the mind
has at its disposal for investigating the laws of phaenomena; the
circumstances which render each of the fundamental modes of exploration
suitable or unsuitable to each class of phaenomena; the extensions and
transformations which the process of investigation has to undergo in
adapting itself to each new province of the field of study; and the
especial gifts with which every one of the fundamental sciences enriches
the method of positive inquiry, each science in its turn being the best
fitted to bring to perfection one process or another. These, and many
cognate subjects, such as the theory of Classification, and the prope