a mental activity of separation, which may be called ab-
straction, and which results in a formal viewpoint distinctive
of a theoretical science. The subject-matter studied may be
the same in all speculative disciplines, but the formal view-
point or vision contemplated definitely leads to the theoreti-
cal distinctions proposed by Aristotle.

The practical sciences are differentiated from the specu-
lative ones by the difference of ends or goals. Speculative
sciences are concerned with knowledge for its own sake;
practical sciences are concerned with knowledge for use as
regards material objects. In the realm of practical sciences,
they are differentiated from each other by the immediacy
or finality of the goal in view. Since some material goods
are means to an end, the practical science concerned with
the end will be superior to the one concerned with the
means, in the same ordered relationship, of course. The
practical sciences are Ethics and Politics, each of which
has many discernible parts. The Productive Sciences are
quite clear from the name and will involve considerations
about all types of making in the realm of materiality, such
as fortifications, shoes, homes, clothes and even human
bodies in regard to which medicine is a health-making
activity. All study should begin with the Organon, which
is not, strictly speaking, a science but an instrument of all
sciences, a propaedeutic or introduction.

The general aim of the Organon is to outline the means
of proceeding correctly in the use of the mind in order to
obtain scientific knowledge in the strict sense. Six treatises
make up the total contents of the Organon and they have
been designated as The Categories, On Interpretation, The
Prior Analytics, The Posterior Analytics, The Topics and The
Sophistical Refutations. As will be evident from what fol-
lows, there is a definite order and arrangement of themes

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