Categorical Propositions in Experimental Research

Propositions are statements. Categorical propositions are statements about categories, that is, about groups or classes. A class is a col­lection of all objects (or entities) that have some special character­istics in common. Categorical propositions are used both as premises and conclusions in the process of deductive argumenta­tion, in which the premises are expected to provide adequate grounds for the truth of the argument’s conclusion. The Theory of Deduction, attributed to Aristotle (384—332 BC), deals with the relation between the premises and conclusions of deductive arguments and further helps determine whether an argument is valid or not. In a valid argument, if the premises are true, the conclusion of the argument is necessarily true. If this is not so, the argument is invalid.

1. Forms of Categorical Propositions

There are four standard forms of categorical propositions; each is briefly described, starting with an illustrative example:

1. Universal affirmative

Example: All factories are companies.

This is an affirmative proposition about two categories: all factories and all companies. Further, it infers that every member of the first-mentioned class (known as the subject term, S) is also a mem­ber of the second-mentioned class (known as the predicate term, P).

Formula: All S are P

2. Universal negative

Example: No factories are companies.

This is a negative statement and infers that, universally, factories are not companies.

Formula: No S are P

3. Particular affirmative

Example: Some factories are companies.

Not all, but some particular, members of the class of factories (at least one) are also members of the class of companies.

Formula: Some S are P

4. Particular negative

Example: Some factories are not companies.

Formula: Some S are not P

Source: Srinagesh K (2005), The Principles of Experimental Research, Butterworth-Heinemann; 1st edition.