The true negatives of _homo est justus--Omnis homo est justus_ are,
_Homo non est justus--Non omnis homo est justus_. If you say, _Homo
est non justus--Omnis homo est non justus_, these are not negative
propositions, but new affirmatives ([Greek: e)k metathe/seôs] in the
language of Theophrastus).]
CHAPTER V.
ANALYTICA PRIORA I.
Reviewing the treatise De Interpretatione, we have followed Aristotle
in his first attempt to define what a Proposition is, to point out
its constituent elements, and to specify some of its leading
varieties. The characteristic feature of the Proposition he stated to
be--That it declares, in the first instance, the mental state of the
speaker as to belief or disbelief, and, in its ulterior or final
bearing, a state of facts to which such belief or disbelief
corresponds. It is thus significant of truth or falsehood; and this
is its logical character (belonging to Analytic and Dialectic), as
distinguished from its rhetorical character, with other aspects
besides. Aristotle farther indicated the two principal discriminative
attributes of propositions as logically regarded, passing under the
names of quantity and quality. He took great pains, in regard to the
quality, to explain what was the special negative proposition in true
contradictory antithesis to each affirmative. He stated and enforced
the important separation of contradictory propositions from contrary;
and he even parted off (which the Greek and Latin languages admit,
though the French and English will hardly do so) the true negative
from the indeterminate affirmative. He touched also upon equipollent
propositions, though he did not go far into them. Thus commenced with
Aristotle the systematic study of propositions, classified according
to their meaning and their various interdependences with each other
as to truth and falsehood--their mutual consistency or
incompatibility. Men who had long been talking good Greek fluently
and familiarly, were taught to reflect upon the conjunctions of words
that they habitually employed, and to pay heed to the conditions of
correct speech in reference to its primary purpose of affirmation and
denial, for the interchange of beliefs and disbeliefs, the
communication of truth, and the rectification of falsehood. To many
of Aristotle's contemporaries this first attempt to theorize upon the
forms of locution familiar to every one would probably appear hardly
less strange than the interrogative dialectic of Sokrates, when he
declared himself not to know what was meant by justice, virtue,
piety, temperance, government, &c.; when he astonished his hearers by
asking them to rescue him from this state of ignorance, and to
communicate to him some portion of their supposed plenitude of
knowledge.