What we call 'common sense' flits easily from one to
another of these inconsistent forms of knowledge,
without realizing their inconsistencies.

At any stage of human culture the function of
philosophy is to bring consistency into the different
accounts, so that we can make a more rational use of
each of them. If we just mix them up together the
result is not only unintelligible, but produces sooner
or later very serious confusion in practical affairs.

It is not the intention of this book to discuss philo-
sophy as it has appeared among different nations and
at different times, but only as it seems to the writer to
appear at present in European and American civiliza-
tion. The book, moreover, only discusses its subject-
matter in broad outlines, and in as few words as
possible.

We can best form an idea of the present-day aspect
of philosophy by surveying briefly the course of
philosophical development in Europe since the seven-
teenth century, in conjunction with the development
of science. Before this time philosophy and theology
were so closely associated that philosophy could
hardly be distinguished from prevailing theological
ideas. With the realization in Renaissance times of
how much pre-Christian civilization had meant, but
more particularly with the rapid development of
physical science and physical conceptions in the time
of Galileo and his scientific successors, contradicting,
as these conceptions did, many accepted theological
ideas, the need arose for more adequate philosophy.

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