t working at the subject."

This, put into the form No not-M is P, is to say that "None who
have not worked can pass". This is equivalent, as the converse by
contraposition, with--

All capable of passing have worked at the subject.

But though Q has worked at the subject, it does not follow that he is
capable of passing. Technically the middle is undistributed. On the
other hand, if he has not worked at the subject, it follows that he
is not capable of passing. We can draw a conclusion at once from the
absence of the necessary condition, though none can be drawn from its
presence alone.

THIRD FIGURE.

Arguments are sometimes advanced in the form of the Third Figure. For
instance: Killing is not always murder: for tyrannicide is not murder,
and yet it is undoubtedly killing. Or again: Unpleasant things
are sometimes salutary: for afflictions are sometimes so, and no
affliction can be called pleasant.

These arguments, when analysed into terms, are, respectively, Felapton
and Disamis.

No tyrannicide is murder;
All tyrannicide is killing;
Some killing is not murder.

Some afflictions are salutary things;
All afflictions are unpleasant things;
Some unpleasant things are salutary things.

The syllogistic form cannot in such cases pretend to be a
simplification of the argument. The argument would be equally
unmistakable if advanced in this form: Some S is not P, for example,
M. Some killing is not murder, _e.g.,_ tyrannicide. Some unpleasant
things are salutary, _e.g.,_ some afflictions.

There is really no "deduction" in the third figure, no leading down
from general to particular. The middle term is only an example of the
minor. It is the syllogism of Contradictory Examples.

In actual debate examples are produced to disprove a universal
assertion, affirmative or negative. Suppose it is maintained that
every wise man has a keen sense of humour. You doubt this: you
produce an instance of the opposite, say Milton. The force of your
contradictory instance is not increased by exhibiting the argument in
syllogistic form: the point is not made clearer.

The Third Figure was perhaps of some use in Yes and No Dialectic.
When you had to get everything essential to your conclusion definitely
admitted, it was useful to know that the production of an example to
refute a generality involved the admission of two propositions. You
must extract from your opponent both that Milton was a wise man, and