ian to expound it.]

[Footnote 3: Some logicians prefer the form Either A is, or B
is. But the two alternatives are propositions, and if "A is"
represents a proposition, the "is" is not the Syllogistic
copula. If this is understood it does not matter: the analysis
of the alternative propositions is unessential.]

CHAPTER VIII.

FALLACIES IN DEDUCTIVE ARGUMENT.--PETITIO PRINCIPII AND
IGNORATIO ELENCHI.

The traditional treatment of Fallacies in Logic follows Aristotle's
special treatise [Greek: Peri sophistikon elenchon]--Concerning
Sophistical Refutations--Pretended Disproofs--Argumentative Tricks.

Regarding Logic as in the main a protection against Fallacies, I have
been going on the plan of taking each fallacy in connexion with its
special safeguard, and in accordance with that plan propose to deal
here with the two great types of fallacy in deductive argument. Both
of them were recognised and named by Aristotle: but before explaining
them it is worth while to indicate Aristotle's plan as a whole.
Some of his Argumentative Tricks were really peculiar to Yes-and-No
Dialectic in its most sportive forms: but his leading types, both
Inductive and Deductive, are permanent, and his plan as a whole has
historical interest. Young readers would miss them from Logic: they
appeal to the average argumentative boy.

He divides Fallacies broadly into Verbal Fallacies ([Greek: para ten
lexin], _in dictione_), and Non-Verbal Fallacies ([Greek: exo tes
lexeos], _extra dictionem_).

The first class are mere Verbal Quibbles, and hardly deserve serious
treatment, still less minute subdivision. The world was young when
time was spent upon them. Aristotle names six varieties, but they
all turn on ambiguity of word or structure, and some of them, being
dependent on Greek syntax, cannot easily be paralleled in another
tongue.

(1) Ambiguity of word ([Greek: homonymia]). As if one were to argue:
"All cold can be expelled by heat: John's illness is a cold: therefore
it can be expelled by heat". Or: "Some afflictions are cheering, for
afflictions are sometimes light, and light is always cheering".
The serious confusion of ambiguous words is met by Definition, as
explained at length in pt. ii. c i.

(2) _Ambiguity of structure_ ([Greek: amphibolia]).

"What he was beaten with was what I saw him beaten with: what I saw
him beaten with was my eye: therefore, what he was beaten with was my
eye."

"How do y