Although it is possible to identify additional features shared by all valid
categorical syllogisms (none of them, for example, have two particular
premises), these six rules are jointly sufficient to
Although it is possible to identify additional features shared by all valid
categorical syllogisms (none of them, for example, have two particular
premises), these six rules are jointly sufficient to
. . . if both premises are universal, then the conclusion must also be
universal. Because we do not assume the existential import of universal
propositions, they cannot be used as premises to establis
. . . at least one premise must be affirmative. Since the exclusion of
the class designated by the middle term from each of the classes
designated by the major and minor terms entails nothing about th
. . . the middle term must be distributed in at least one premise. In
order to effectively establish the presence of a genuine connection
between the major and minor terms, the premises of a syllogism
. . . the middle term must be distributed in at least one premise. In
order to effectively establish the presence of a genuine connection
between the major and minor terms, the premises of a syllogism
. . . there must be exactly three unambiguous categorical terms. The
use of exactly three categorical terms is part of the definition of a
categorical syllogism, and we saw earlier that the use of an
Since the validity of a categorical syllogism depends solely upon its
logical form, it is relatively simple to state the conditions under which
the premises of syllogisms succeed in guaranteeing the t