An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

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CHAPTER VIII.
THE GENERAL NATURE OF INDUCTION.
i. IN passing to "Inductive Logic," we must return
to a point which we reached in the preceding chapter,
the relation of hypothetical to categorical propositions.
"
The hypothetical,
If anything is M it is P," and the
categorical universal, "Every M is P," correspond to the
two sides of a Term, intension and extension. The
categorical form refers primarily to the real instances in
which M is found. But when we concentrate attention
on the attributes, neglecting any particular embodiment
of them, the proposition becomes an assertion of a
necessary connection of these attributes, a "general
law." To make this connection explicit, the natural
form is that of the hypothetical proposition,
"
If any
thing is M it is P," or
"
If S is M it is P." The hypo
thetical form is adopted not to express any uncertainty
in the matter, but because we do not wish to refer to
any particular instances. To say that
gravitate"
"
material bodies
is to say, without reference to any special
case, "if material, then gravitating." The absence of
reference to any particular objects (in space and time)
is most evident in geometrical judgments, for the figures
with which they deal are never perfectly realised in the
concrete. In some cases the hypothetical antecedent is
impossible of realisation, as in the first law of motion,