sign
anything known in which something else is known
instrumental sign
a thing that exists in its own right but also serves as a sign
formal sign
sign that has no existence apart from its role as a sign (examples: phantasms and thoughts about a thing)
natural sign
either formal or instrumental; a sign whose meaning is determined by the nature of the very thing that is the sign
conventional sign
must be instrumental; a sign whose meaning is determined by human will
predicable
a relationship (essential or non essential) between the subject and predicate
genus (essential predicable)
a universal said of a subject as part of the essence of that subject (example: the genus of blue is color)
specific difference (essential predicable)
a universal said of a subject as part of the essence of that subject (example: the spec. diff. of a triangle from other rectilinear figures is that it is 3 sided.)
species (essential predicable)
a universal said of a subject as the whole essence of that subject (genus + specific difference) (example: a triangle’s species is a 3 sided rectilinear figure)
accident (nonessential predicable)
a universal said of a subject which may or may not belong to that subject while it remains the same kind of thing (example: the rose is red; all roses do not have to be red).
property (nonessential predicable)
a universal said of a subject that does not belong essentially to the subject but it does belong necessarily and exclusively to that subject. (example: a human being is risible; able to laugh).
extension
the set of objects falling under a concept (large extension to small extension: animal – cat – siamese)
comprehension
the set of intelligible notes that together constitute the elements of a concept (large comprehension to small comprehension: beagle – dog – animal)
univocal
use of one term to signify one concept (example: fruit said of apple and banana)
equivocal
use of one term to signify two different concepts (example: bat said of the animal and of the baseball equipment)
terms that cannot be categorized
composite terms (ex: blue bell, red leaf)
singulars and not universals (ex: socrates)
negative terms (ex: nonhuman)
transcendentals (ex: good, thing, true)
distributed term
all
undistributed term
some
A term
all A are B
E term
no A are B
I term
some A are B
O term
some A are not B
singular (affirmative and negative)
x is B, x is not B
indefinite (affirmative and negative)
A are B, A are not B
contradictory (square of opposition)
diagonal; if one is true, the other is false and vice versa
contrary (square of opposition)
horizontal A and E; starting with true, the other is false. starting with false, the other is undetermined
subcontrary (square of opposition)
horizontal with I and O; starting with false, the other is true. starting with true, the other is undetermined
subalternate (square of opposition)
starting with A or E, goes down; descends with truth, starting with false makes other undetermined
superalternate (square of opposition)
starting with I or O and goes up; goes up with falsity, starting with true makes other undetermined
middle term
only in the premises
major term
predicate of conclusion and in major premise
minor term
subject of conclusion and in minor premise
figure one (categorical syllogisms)
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figure two (categorical syllogisms)
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figure three (categorical syllogisms)
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figure four (categorical syllogisms)
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