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 distinguish between
valid and invalid syllogisms.
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 distinguish between
valid and invalid syllogisms.
. . . 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 establish the existential
import that is part of any particular
. . . 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 the
relationship between those two classes, nothing follo
. . . 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 must
provide some information about the entire class d
. . . 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 must
provide some information about the entire class d
. . . 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 ambiguous
term in more than one of its senses amounts t
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 truth of their
conclusions. Relying heavily upon the med