sciences to philosophy is not so close.

Thus, the sciences of arithmetic, algebra, and geometry may be
successfully prosecuted by a man who has reflected little upon the
nature of numbers and who has never asked himself seriously what he
means by space. The assumptions which he is justified in making, and
the kind of operations which he has the right to perform, do not seem,
as a rule, to be in doubt.

So it is also in the sciences of chemistry and physics. There is
nothing to prevent the chemist or the physicist from being a
philosopher, but he is not compelled to be one. He may push forward
the investigations proper to his profession regardless of the type of
philosophy which it pleases him to adopt. Whether he be a realist or
an idealist, a dualist or a monist, he should, as chemist or physicist,
treat the same sort of facts in the same sort of a way. His path
appears to be laid out for him, and he can do work the value of which
is undisputed by traveling quietly along it, and without stopping to
consider consciously what kind of a path it is. There are many who
work in this way, and they succeed in making important contributions to
human knowledge.

Such sciences as these I call the non-philosophical sciences to
distinguish them from the group of sciences I have been discussing at
length. What marks them out is, that the facts with which the
investigator has to deal are known by him with sufficient clearness to
leave him usually in little doubt as to the use which he can make of
them. His knowledge is clear enough for the purpose in hand, and his
work is justified by its results. What is the relation of such
sciences as these to philosophy?