Types of Syllogism

Categorical Syllogisms The Structure of Syllogism. Now, on to the next level, at which we combine more than one categorical proposition to fashion logical arguments.

Syllogism takes the form of enthymeme when it is compressed. Enthymeme combines the minor premise and the conclusion, omitting the major statement. For instance, a syllogism “All dogs are canine.

Conditional syllogisms are seldom completed with all three sentences -- often only the major and minor premises are needed and sometimes only the major premise is enough. The conclusion of the conditional syllogism is often unspoken and it is intended that the listener infers it for themselves.

In classical logic, disjunctive syllogism (historically known as modus tollendo ponens (MTP), Latin for "mode that affirms by denying") is a valid argument form which is a syllogism having a disjunctive statement for one of its premises. An example in English: The breach is a safety violation, or it is not subject to fines.

A categorical syllogism consists of three parts: Major premise; Minor premise; Conclusion; Each part is a categorical proposition, and each categorical proposition contains two categorical terms. In Aristotle, each of the premises is in the form "All A are B," "Some A are B", "No A are B" or "Some A are not B", where "A" is one term and "B" is another.

The major premise links M with P and the minor premise links M with S. However, the middle term can be either the subject or the predicate of each premise where it appears. The differing positions of the major, minor, and middle terms gives rise to another classification of syllogisms known as the figure.