Handbook of the History of Logic: - Fordham University Faculty

316 Henrik Lagerlund
This definition reflects the absolute fundamental aspect of logic for the scholastics.
Logic is a tool or an art for them presupposed in all science. All study must start
with logic. 83
Dialectics or argumentation presupposes discourse (sermone), and discourse
presupposes utterance (vox), which in turn is sound (sono) of a special kind. A
sound is either an utterance or not. If it is not an utterance, then it is not of
interest to logic. An utterance is either significative or not. An utterance which
is significative is a sound which represents something, like for example ‘human
being’. A non-significative utterance does not represent anything, like ‘buba’.
A significative utterance is either a name (nomine) oraverb(verbo). It is a
name if it signifies conventionally something without a time, while a verb signifies
conventionally (ad placitum) something with a time. The difference is simply that
since a verb signifies a doing of something, it requires time in which the doing takes
place, but a name is atemporal; it does not require time for naming something.
An expression (oratio) is a complex significative utterance, that is, it is a sentence
like ‘The human being is white’. There are also two kinds of expressions,
namely perfect or proper expressions and imperfect or improper expressions. An
improper expression is, for example, ‘white human being’. It is improper since it
does not contain both a name and a verb. There are, of course, different kinds of
expressions according to the different grammatical modes, like indicative, imperative,
imperative, perfect etc., but only indicative expressions are called proposition
and hence only they are important for logic.
A proposition is hence a perfect or proper expression in the indicative mode,
which is either true or false. There are furthermore two kinds of propositions,
namely categorical and hypothetical. The two kinds of propositions also divide
into two kinds of logics; one for categorical propositions and the other for hypothetical.
Let us first deal with the categorical propositions, since they are the most
important ones.
A categorical proposition is a proposition that has a subject and a predicate
as its principle parts. In the proposition ‘A human being runs’ (‘homo currit’),
‘human being’ and ‘runs’ are respectively the subject and the predicate. The
logical form of this proposition is not ‘A human being runs’, however, since there
is a copula or something binding the subject and predicate (or verb) assumed in
between them. The logical form is therefore ‘A human being is running’.
Categorical propositions are divided into universal, particular, indefinite, and
singular. The most familiar ones are the following:
Universal: ‘Every human being is running’
Particular: ‘Some human being is running’
Indefinite: ‘A human being is running’
Singular: ‘Socrates is running’ or ‘That human is running’
83 Logic is part of the science of discourse (scientia sermocinalis), which has three parts, namely
grammar, rhetoric and logic. This view was defended by both Peter and William.