y difficult and trying species of disputative pastime, in
which we find the genesis of Aristotle's logical treatises.

To get a proper idea of this debate by Question and Answer, which we
may call Socratic disputation after its most renowned master, one
must read some of the dialogues of Plato. I will indicate merely
the skeleton of the game, to show how happily it lent itself to
Aristotle's analysis of arguments and propositions.

A thesis or proposition is put up for debate, _e.g._, that knowledge
is nothing else than sensible perception,[2] that it is a greater
evil to do wrong than to suffer wrong,[3] that the love of gain is not
reprehensible.[4] There are two disputants, but they do not speak on
the question by turns, so many minutes being allowed to each as in
a modern encounter of wits. One of the two, who may be called the
Questioner, is limited to asking questions, the other, the Respondent,
is limited to answering. Further, the Respondent can answer only "Yes"
or "No," with perhaps a little explanation: on his side the Questioner
must ask only questions that admit of the simple answer "Yes" or "No".
The Questioner's business is to extract from the Respondent admissions
involving the opposite of what he has undertaken to maintain. The
Questioner tries in short to make him contradict himself. Only a very
stupid Respondent would do this at once: the Questioner plies him
with general principles, analogies, plain cases; leads him on from
admission to admission, and then putting the admissions together
convicts him out of his own mouth of inconsistency.[5]

Now mark precisely where Aristotle struck in with his invention of the
Syllogism, the invention on which he prided himself as specially his
own, and the forms of which have clung to Logic ever since, even
in the usage of those who deride Aristotle's Moods and Figures as
antiquated superstitions. Suppose yourself the Questioner, where did
he profess to help you with his mechanism? In effect, as the word
Syllogism indicates, it was when you had obtained a number of
admissions, and wished to reason them together, to demonstrate how
they bore upon the thesis in dispute, how they hung together, how they
necessarily involved what you were contending for. And the essence of
his mechanism was the reduction of the admitted propositions to common
terms, and to certain types or forms which are manifestly equivalent
or inter-dependent. Aristotle advised his pupils also in