Bacon holds that philosophy has for its objects God, man, and nature,
and he regards it as within his province to treat of "_philosophia
prima_" (a sort of metaphysics, though he does not call it by this
name), of logic, of physics and astronomy, of anthropology, in which he
includes psychology, of ethics, and of politics. In short, he attempts
to map out the whole field of human knowledge, and to tell those who
work in this corner of it or in that how they should set about their
task.

As for Descartes, he writes of the trustworthiness of human knowledge,
of the existence of God, of the existence of an 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,