external world, of the
human soul and its nature, of mathematics, physics, cosmology,
physiology, and, in short, of nearly everything discussed by the men of
his day. No man can accuse this extraordinary Frenchman of a lack of
appreciation of the special sciences which were growing up. No one in
his time had a better right to be called a scientist in the modern
sense of the term. But it was not enough for him to be a mere
mathematician, or even a worker in the physical sciences generally. He
must be all that has been mentioned above.

The conception of philosophy as of a something that embraces all
departments of human knowledge has not wholly passed away even in our
day. I shall not dwell upon Spinoza (1632-1677), who believed it
possible to deduce a world _a priori_ with mathematical precision; upon
Christian Wolff (1679-1754), who defined philosophy as the knowledge of
the causes of what is or comes into being; upon Fichte (1762-1814), who
believed that the philosopher, by mere thinking, could lay down the
laws of all possible future experience; upon Schelling (1775-1854),
who, without knowing anything worth mentioning about natural science,
had the courage to develop a system of natural philosophy, and to
condemn such investigators as Boyle and Newton; upon Hegel (1770-1831),
who undertakes to construct the whole system of reality out of
concepts, and who, with his immediate predecessors, brought philosophy
for a while into more or less disrepute with men of a scientific turn
of mind. I shall come down quite to our own times, and consider a man
whose conception of philosophy has had and still has a good deal of
influence, especially with the general public--with those to whom
philosophy is a thing to be taken up in moments of leisure, and cannot
be the serious pursuit of a life.

"Knowledge of the lowest kind," says Herbert Spencer, "is _un-unified_
knowledge; Science is _partially-unified_ knowledge; Philosophy is
_completely-unified_ knowledge." [1] Science, he argues, means merely
the family of the Sciences--stands for nothing more than the sum of
knowledge formed of their contributions. Philosophy is the fusion of
these contributions into a whole; it is knowledge of the greatest
generality. In harmony with this notion Spencer produced a system of
philosophy which includes the following: A volume entitled "First
Principles," which undertakes to show what man can and what man cannot
know; a treatise on