- Categorical Proposition
The Aristotelian or classical study of deduction focuses on arguments containing propositions of a special kind: called "categorical propositions". Categorical propositions are propositions that make declarations about entities belonging to, or not belong to, categories or classes. All categorical statements relate two classes or categories in some manner: we call these two terms the subject "S" and the predicate "P".
To understand all the parts of a categorical syllogism, first consider the following arguments:
No soldiers are cowards All marines are soldiers Therefore, no marines are cowards
and
Some Men are professorsSome professors are not tenured Some men are not tenured.
All three of the propositions in this argument are categorical propositions. These propositions either affirm or deny that some class (S) is included in some other class (P), either in whole, or in part. There are 4 ways in which two classes or categories may be related to each other:
1) Every member of the first class is also a member of the second class - "All S are P". (All marines are soldiers)
2) Some but not all members of one class are also a member of the second class "Some S are P" (Some men are professors)
3) Some but not all members of one class are not a member of the second class "Some S are not P" (Some professors are not tenured)
4) The two classes have no members in common "No S are P" (No soldiers are cowards)
Here are the 4 types of propositions in brief form:
All S are P No S are P Some S are P Some S are not P
Every standard form categorical proposition also has a quality, a quantity, and a specific manner of distributing the Subject and Predicate categories within the statement. Does this appear daunting at this point? While this may seem confusing right now, read through the following sections, and all will become clear.
Hypothetical Propositions – A hypothetical proposition is one whose predicate does not assert of the subject in an absolute manner. There are three kinds of hypothetical propositions:
a.conditional (if…, then…) – the assertion of the consequent is dependent upon
the condition established by the antecedent.
If the elections will not push through then there will violence in the country.
b.disjunctive (either…, or…) – affirms the possibility of one or more of the
alternatives.
A candidate for public office is either qualified on unqualified.
c.conjunctive (not both…, and…) – denies the simultaneous possibility of both
alternatives.
The farmer cannot be environment friendly and not environment friendly at the
same time.
