SYLLOGISM

Definition:
In logic, a form of deductive reasoning consisting of a major premise, a minor premise, and a conclusion. Adjective: syllogistic.

Here is an example of a valid categorical syllogism:

Major premise: All mammals are warm-blooded.
Minor premise: All black dogs are mammals.
Conclusion: Therefore, all black dogs are warm-blooded.


Types of syllogism

Although there are infinitely many possible syllogisms, there are only a finite number of logically distinct types. We shall classify and enumerate them below. Note that the syllogism above has the abstract form:
Major premise: All M are P.
Minor premise: All S are M.
Conclusion: All S are P.
The premises and conclusion of a syllogism can be any of four types, which are labeled by letters[3] as follows. The meaning of the letters is given by the table:
code quantifier subject copula predicate type example
a All S are P universal affirmatives All humans are mortal.
e No S are P universal negatives No humans are perfect.
i Some S are P particular affirmatives Some humans are healthy.
o Some S are not P particular negatives Some humans are not clever.