Categorical Propositions-legal Technique.docx

CATEGORICAL PROPOSITIONS Introduction: In this Chapter, the reader will learn the relationship of a premise and its conclusion in general. It will show how an argument can be valid or invalid through the presentation of its premise and conclusion and learn about the four (4) kinds of Categorical proposition which also shows the relationship of one category to another category. DEDUCTIVE ARGUMENT defined- an argument whose premises are claimed to provide conclusive grounds for the truth of its conclusion. VALIDITY: a characteristic of any deductive argument whose premises, if they were all true would provide conclusive grounds for the truth of its conclusion. Such an argument is said to be valid. CLASSICAL or ARISTOTELIAN LOGIC: The traditional account of syllogistic reasoning, in which certain interpretations of categorical propositions are presupposed. MODERN or MODERN SYMBOLIC LOGIC: The account of syllogistic reasoning accepted today. It differs in important ways from the traditional account. 1. Classes and Categorical Propositions CLASSICAL LOGIC- deals mainly with arguments based on the relations of classes of objects to one another. Class defined- a collection of all objects that have specified characteristic in common. Three ways to immediately see how two classes can be related 1. Wholly included or wholly contained-All in One class may be included in all of another class. Example: Dogs is wholly included in the class of all mammals. 2. Partially included or partially contained- Some of the members of one class may be included in another class. Example: All singers are partially included in the class of all females. 3. Two classes may have no members in common. Example: Thus the class of all triangles and the class of all circles may be said to exclude one another. *In a deductive argument, we present propositions that state the relations between one category and another category. CATEGORICAL PROPOSITIONS- propositions with which such arguments are formulated; building blocks of argument in the classical account of deductive logic. Example:

No athletes are vegetarians. All football players are athletes. Therefore no football players are vegetarians. In this illustrative argument the three categorical propositions are about the class of all athletes, class of all vegetarians, and the class of all football players and each premise affirms or denies that some class “S” is included in some other class “P” in whole or in part. The FOUR kinds of Categorical Propositions Standard-form categorical propositions 1. 2. 3. 4.

All Politicians are liars No politicians are liars Some politicians are liars Some politicians are not liars *S for “subject class” and P for “predicate class”

1. UNIVERSAL AFFIRMATIVE PROPOSITIONS- it is asserted that the whole of a class is included or contained in another class. All S is P. Example: All lawyers are wealthy people. 2. UNIVERSAL NEGATIVE PROPOSITIONS- It asserts that the subject class, S, is wholly excluded from the predicate class P. No S is P. Example: No criminals are good citizens.

3. PARTICULAR AFFIRMATIVE PROPOSITIONS- it does not affirm or deny anything about a specific class; it makes no pronouncements about the entire class. Two different classes have “Some” member or members in common. Some S is P. Example: Some chemicals are poisons.

4. PARTICULAR NEGATIVE PROPOSITIONS- it does not affirm the inclusion of some members of the first class in the second class; this is precisely what denied is.

Some S is not P. Example: Some insects are not pests.

These propositions are the building blocks of deductive arguments. In each of these FOUR standard forms a relation is expressed between a subject class and a predicate class. CONCLUSION: We can now say that in understanding Categorical Propositions, we need to know our subject, predicate and know what the statement is trying to prove in connection with the relationship of its premise and conclusion. Analyze propositions by distinguishing the relationship of one category to another through these A, E, I, O kinds of propositions. The Following topics will further provide a clearer view on how we can better understand categorical propositions and its kinds.