(2) To convert A. or O. simply, as—­

    All Money is Wealth .’.  All Wealth is Money;

or—­Some Wealth is not Money .’.  Some Money is not Wealth.

In both these cases, Wealth, though undistributed in the convertend, is distributed in the converse.

(3) To attempt to syllogise with two premises containing four terms, as

      The Papuans are savages;
      The Javanese are neighbours of the Papuans: 
    .’.  The Javanese are savages.

Such an argument is excluded by the definition of a Syllogism, and presents no formal evidence whatever.  We should naturally assume that any man who advanced it merely meant to raise some probability that ‘neighbourhood is a sign of community of ideas and customs.’  But, if so, he should have been more explicit.  There would, of course, be the same failure of connection, if a fourth term were introduced into the conclusion, instead of into the premises.

(4) To distribute in the conclusion a term that was undistributed in the premises (an error essentially the same as (2) above), i.e., Illicit process of the major or minor term, as—­

      Every rational agent is accountable;
      Brutes are not rational agents: 
    .’.  Brutes are not accountable.

In this example (from Whately), an illegitimate mood of Fig.  I., the major term, ‘accountable,’ has suffered the illicit process; since, in the premise, it is predicate of an affirmative proposition and, therefore, undistributed; but, in the conclusion, it is predicate of a negative proposition and, therefore, distributed.  The fact that nearly everybody would accept the conclusion as true, might lead one to overlook the formal inconclusiveness of the proof.

Again,

      All men are two-handed;
      All two-handed animals are cooking animals: 
    .’.  All cooking animals are men.

Here we have Bramantip concluding in A.; and there is, formally, an illicit process of the minor; though the conclusion is true; and the evidence, such as it is, is materially adequate. (’Two-handed,’ being a peculiar differentia, is nugatory as a middle term, and may be cut out of both premises; whilst ‘cooking’ is a proprium peculiar to the species Man; so that these terms might be related in U., All men are all cookers; whence, by conversion, All cookers are men.)

(5) To omit to distribute the middle term in one or the other premise, as—­

      All verbal propositions are self-evident;
      All axioms are self-evident: 
    .’.  All axioms are verbal propositions.

This is an illegitimate mood in Fig.  II.; in which, to give any conclusion, one premise must be negative.  It may serve as a formal illustration of Undistributed Middle; though, as both premises are verbal propositions, it is (materially) not syllogistic at all, but an error of classification; a confounding of co-ordinate species by assuming their identity because they have the generic attribute in common.