| Categorical propositions | Propositions that are equivalent to one of four forms--"All A is B," "No A is B," "some A is B" and "Some A is not B."
|
 |
|
|
| Categorical syllogism | A syllogism consisting only of categorical propositions.
|
|
|
|
| Distribution | A subject or predicate is distributed if, as a class, its members all have the characteristic in question. If the claim is universal, the subject is then distributed, because you are saying that all of the members of the subject class either have or don't have some characteristic. If the claim is negative, the predicate is distributed.
|
|
|
|
| Figure of a syllogism | The figure of the syllogism is the location of the middle term. Letting P = major term, S = minor term, and M = middle term, the figure of a syllogism has to do with the placement of M, the middle term. There are four possible locations (remember the major term, P, will be in the first premise and the minor term S will be in the second premise -- so all you need to know to set out the syllogism is where the middle term is to be found).
|
|
|
|
| Major premise | The major premise is the premise of a syllogism containing the major term (the predicate of the conclusion)
|
|
|
|
| Major term | The predicate of the conclusion in a syllogism.
|
|
|
|
| Middle term | The term that only appears in the two premises of a syllogism.
|
|
|
|
| Minor premise | The minor premise is the premise of a syllogism containing the minor term.
|
|
|
|
| Minor term | The subjecxt of the conclusion in a syllogism.
|
|
|
|
| Mood of a syllogism | The mood of a syllogism is the list of the types of claims (A, E, I, and O) of the major premise, minor premise, and conclusion (in that order). Since there are the two premises and one conclusion, you will have three letters indicating the categorical propositions that constitute the syllogism.
|
|
|
|
| Particular proposition | This is a proposition that can be written in the form "Some A is B," "Some A is not B" or "x% of A are/are not B."
|
|
|
|
| Quantifier | A term that indicates "how much"; such as the universal quantifiers "all" or "no" and the particular quantifier "some." Statistical propositions of the form x% of A is B (x is neither 0 nor 100) are treated as particular propositions.
|
|
|
|
| Rules of the Syllogism | The rules of the syllogism are the conditions that must be met in order for the syllogism to be valid.
|
|
|
|
| Soundness | A sound argument is valid and has true premises. That is, the premises sufficiently support the conclusion and the premises are true as well. In a sound argument, the conclusion is also true.
|
|
|
|
| Standard Form of a Categorical Syllogism | A syllogism in which the propositions are all expressed in the form of an A, E, I, or O claim ("All A is B," "No A is B," "Some A is B," Some A is not B."
|
|
|
|
| Syllogism | This is a three line argument with two premises and one conclusion in which there are only three terms (called the major term, the minor term, and the middle term).
|
|
|
|
| Universal proposition | A proposition that is "all" or "nothing"--i.e., it can be expressed in the form "All A is B" or "No A is B."
|
|
|
|
| Validity | An argument that is structurally correct (so that if the premises were true, the conclusion could not be false). Only arguments can be valid or invalid. Validity is thought to be a matter only of deductive, not inductive, logic. In valid deductive arguments the premises could not be true and the conclusion false. The conclusion comes out of the premises, by the very structure of the argument
|