henomena, with a mixture of the
ideas belonging to them severally, caused many perplexities, which may
be noticed under Fallacies of Confusion.

CHAPTER VI.

FALLACIES OF RATIOCINATION.

These fallacies (to which the name _Fallacy_ is commonly applied
exclusively) would generally be detected if the arguments were set out
formally; and the value of the syllogistic rules is, that they force the
reasoner to be aware what it is that he is really asserting. The
frequent errors in processes such as Conversion and Opposition, which
are in appearance, though not in reality, inferences from premisses, may
for convenience be here referred to. Such are the simple conversion of
an universal affirmative; the corresponding error in a hypothetical
proposition of inferring the truth of the antecedent from that of the
consequent; and the confusing of a contrary with a contradictory, which
amounts, in practice, to mistaking the reverse of wrong for right. But
fallacies of Ratiocination properly lie in syllogisms. They commonly
resolve themselves, when in a single syllogism, into the having more
than three terms, whether covertly, as through an undistributed middle,
or an illicit process, or avowedly. But the most dangerous and the
commonest of these fallacies arise in a chain of argument from _changing
the premisses_. One of the obscurer forms of this is the fallacy _a
dicto secundum quid_ (i.e. with a qualification, or condition,
expressed, or, more usually, understood) _ad dictum simpliciter_. Thus,
the Mercantile Theory was in favour of prohibiting all trade which tends
to carry out more money than it brings in, on the ground that money is
riches, though it is so only if the money can be _freely_ spent. Such,
too, was the argument (used to support the doctrine that tithes fall on
the landlord) that, because now the rent of tithe-free land exceeds that
of tithed land, the rent from the latter would be increased by the
abolition of all tithes. There was a similar fallacy in the use of the
maxim, that individuals are the best judges of their pecuniary
interests, against Mr. Wakefield's scheme for concentrating settlers.
Cases in which the condition of _time_ is dropped, fall under this same
particular fallacy, as, when the maxim that prices always find their
level, is construed as meaning that they are always _at_ their level. It
is the same with the reasoning (especially in political and social
subjects), upon principles, whi