With a view to showing the truth of this opinion, I shall take up one
by one the philosophical sciences. Of the history of philosophy I
shall not speak in this part of the work, but shall treat of it in
Chapter XXIII.

66. THE TRADITIONAL LOGIC.--Most of us begin our acquaintance with
logic in the study of some such elementary manual as Jevons' "Lessons
in Logic."

In such books we are shown how terms represent things and classes of
things or their attributes, and how we unite them into propositions or
statements. It is indicated at length what statements may be made on a
basis of certain other statements and what may not; and emphasis is
laid upon the dangers which arise out of a misunderstanding of the
language in which we are forced to express our thoughts. Finally,
there are described for us the experimental methods by which the
workers in the sciences have attained to the general information about
the world which has become our heritage.

Such books are useful. It is surely no small profit for a student to
gain the habit of scrutinizing the steps by which he has come into the
possession of a certain bit of information, and to have a quick eye for
loose and inconsistent reasonings.

But it is worthy of remark that one may study such a book as this and
yet remain pretty consistently on what may be called the plane of the
common understanding. One seems to make the assumptions made in all
the special sciences, _e.g._ the assumption that there is a world of
real things and that we can know them and reason about them. We are
not introduced to such problems as: What _is_ truth? and Is _any_