the ships can come in: they may
be excluded by other causes. And so, though they cannot come in, it
does not follow that the harbour is frozen.

QUESTIONS CONNECTED WITH HYPOTHETICAL SYLLOGISMS.

(1) _Are they properly called Syllogisms?_ This is purely a question
of Method and Definition. If we want a separate technical name for
forms of argument in which two terms are reasoned together by means of
a third, the Hypothetical Syllogism, not being in such a form, is
not properly so called. The fact is that for the purposes of the
Hypothetical Argument, we do not require an analysis into terms at
all: it is superfluous: we are concerned only with the affirmation or
denial of the constituent propositions as wholes.

But if we extend the word Syllogism to cover all arguments in which
two propositions necessarily involve a third, the Hypothetical
Argument is on this understanding properly enough called a Syllogism.

(2) _Is the inference in the Hypothetical Syllogism Mediate or
Immediate?_

To answer this question we have to consider whether the Conclusion
can be drawn from either of the two premisses without the help of the
other. If it is possible immediately, it must be educible directly
either from the Major Premiss or from the Minor.

(_a_) Some logicians argue as if the Conclusion were immediately
possible from the Major Premiss. The Minor Premiss and the Conclusion,
they urge, are simply equivalent to the Major Premiss. But this is a
misunderstanding. "If A is B, C is D," is not equivalent to "A is B,
_therefore_ C is D". "If the harbour is frozen, the ships cannot come
in" is not to say that "the harbour is frozen, and therefore," etc.
The Major Premiss merely affirms the existence of the relation of
Reason and Consequent between the two propositions. But we cannot
thereupon assert the Conclusion unless the Minor Premiss is also
conceded; that is, the inference of the Conclusion is Mediate, as
being from two premisses and not from one alone.

(_b_) Similarly with Hamilton's contention that the Conclusion
is inferrible immediately from the Minor Premiss, inasmuch as the
Consequent is involved in the Reason. True, the Consequent is involved
in the Reason: but we cannot infer from "A is B" to "C is D," unless
it is conceded that the relation of Reason and Consequent holds
between them; that is, unless the Major Premiss is conceded as well as
the Minor.

(3) _Can Hypothetical Syllogism be reduced to the Categ