it recoils upon the
sophist; for there is no sense in quoting men against one another,
unless both (or all) are acknowledged to speak with the authority of
learning and judgment, and therefore the general doctrine which they
hold in common is the more confirmed.

This is an example of the paralogism of 'proving too much'; when a
disputant is so eager to refute an opponent as to lay down, or imply,
principles from which an easy inference destroys his own position. To
appeal to a principle of greater sweep than the occasion requires may
easily open the way to this pitfall: as if a man should urge that 'all
men are liars,' as the premise of an argument designed to show that
another's assertion is less credible than his own.

A common form of _ignoratio elenchi_ is that which Whately called the
'fallacy of objections': namely, to lay stress upon all the
considerations against any doctrine or proposal, without any attempt to
weigh them against the considerations in its favour; amongst which
should be reckoned all the considerations that tell against the
alternative doctrines or proposals. Incontestable demonstration can
rarely be expected even in science, outside of the Mathematics; and in
practical affairs, as Butler says, 'probability is the very guide of
life'; so that every conclusion depends upon the balance of evidence,
and to allow weight to only a part of it is an evasion of the right
issue.

Sec. 8. Fallacies in the connection of premises and conclusion, that cannot
be detected by reducing the arguments to syllogistic form, must depend
upon some juggling with language to disguise their incoherence. They may
be generally described as Fallacies of Ambiguity, whether they turn upon
the use of the same word in different senses, or upon ellipsis. Thus it
may be argued that all works written in a classical language are
classical, and that, therefore, the history of Philosophy by Diogenes
Laertius, being written in Greek, is a classic. Such ambiguities are
sometimes serious enough; sometimes are little better than jokes. For
jokes, as Whately observes, are often fallacies; and considered as a
propaedeutic to the art of sophistry, punning deserves the ignominy that
has overtaken it.

Fallacies of ellipsis usually go by learned names, as; (1) _a dicto
secundum quid ad dictum simpliciter_. It has been argued that since,
according to Ricardo, the value of goods depends solely upon the
quantity of labour necessary to prod