Handbook of the History of Logic: - Fordham University Faculty

The Development of Supposition Theory in the Later 12 th through 14 th Centuries 167
The names of the individual moods are from Peter of Spain. [Peter of Spain
T IV.13 (46)] These names are post-Aristotelian inventions; they are cleverly devised
so as to encode useful logical information. Medieval students were expected
to memorize a verse consisting of the names:
Barbara Celarent Darii Ferio Baralipton
Celantes Dabitis Fapesmo Frisesomorum.
Cesare Cambestres Festino Barocho Darapti.
Felapto Disamis Datisi Bocardo Ferison.
The names contain codes which show how to mimic Aristotle’s reduction of all
moods to the first figure direct modes. 12
12Here are Peter’s instructions for doing this (translation from [Kretzman and Stump, pp.
224–25 and 222]):
“In these four verses there are nineteen words that are associated with the nineteen
moods of the three figures . . .
“It is important to know that the vowels A, E, I, and O stand for the four types
of propositions. The vowel A stands for a universal affirmative; E for a universal
negative; I for a particular affirmative; and O for a particular negative.
“Again, there are three syllables in each word (if there is any more, it is superfluous,
except for M, as will be clear later). The first of these three syllables stands
for the major proposition of the syllogism; the second stands for the minor; the
third for the conclusion. For example, the first word — Barbara — has three
syllables, in each of which A is used; the three occurrences of A signify that the
first mood of the first figure consists of two universal affirmative premises resulting
in a universal affirmative conclusion. (The vowels used in the other words should
also be understood in this way.)
“Again, it is important to know that the first four words of the first verse and all
the other subsequent words begin with these consonants: B, C, D, andF . In this
way we are given to understand that all the moods that a word beginning with B
stands for should be reduced to the first mood of the first figure; all the moods
signified by a word beginning with C, to the second mood of the first figure; D, to
the third mood; F , to the fourth.
“Again, where S is used in these words, it signifies that the proposition that the
immediately preceding vowel stands for requires simple conversion. And P signifies
that the proposition requires conversion per accidens. And where M is used, it signifies
that the premises require transposition. (Transposition is making the major
premise the minor premise, and vice versa.) And where C is used [after a vowel]
it signifies that the mood that word stands for should be proved by reduction per
impossibile.
“The fourth mood [of the second figure] consists of a universal affirmative and
a particular negative premise, resulting in a particular negative conclusion. For
example [BAROCHO],
Every man is an animal;
some stone is not an animal;
therefore, some stone is not a man.
And this is reduced to the first mood of the first figure [BARBARA] by a reduction
per impossibile.
[Reduction per impossibile]