ore given, admitted, or assumed
propositions, called the PREMISS or PREMISSES.

When the conclusion is drawn from one proposition, the inference is
said to be IMMEDIATE; when more than one proposition is necessary to
the conclusion, the inference is said to be MEDIATE.

Given the proposition, "All poets are irritable," we can immediately
infer that "Nobody that is not irritable is a poet"; and the one
admission implies the other. But we cannot infer immediately that "all
poets make bad husbands". Before we can do this we must have a second
proposition conceded, that "All irritable persons make bad husbands".
The inference in the second case is called Mediate.[1]

The modes and conditions of valid Mediate Inference constitute
Syllogism, which is in effect the reasoning together of separate
admissions. With this we shall deal presently. Meantime of Immediate
Inference.

To state all the implications of a certain form of proposition, to
make explicit all that it implies, is the same thing with showing
what immediate inferences from it are legitimate. Formal inference, in
short, is the eduction of all that a proposition implies.

Most of the modes of Immediate Inference formulated by logicians are
preliminary to the Syllogistic process, and have no other practical
application. The most important of them technically is the process
known as Conversion, but others have been judged worthy of attention.

AEQUIPOLLENT OR EQUIVALENT FORMS--OBVERSION.

AEquipollence or Equivalence ([Greek: Isodynamia]) is defined as the
perfect agreement in sense of two propositions that differ somehow in
expression.[2]

The history of AEquipollence in logical treatises illustrates two
tendencies. There is a tendency on the one hand to narrow a theme
down to definite and manageable forms. But when a useful exercise is
discarded from one place it has a tendency to break out in another
under another name. A third tendency may also be said to be specially
well illustrated--the tendency to change the traditional application
of logical terms.

In accordance with the above definition of AEquipollence or
Equivalence, which corresponds with ordinary acceptation, the term
would apply to all cases of "identical meaning under difference of
expression". Most examples of the reduction of ordinary speech into
syllogistic form would be examples of aequipollence; all, in fact,
would be so were it not that ordinary speech loses somewhat in the
process