## The logic quiz: true or false

Each item is worth 4 points for a total of 100 points. Scale: 1 to 3 Wrong. Review sections relevant to the content and do the exercises of the quiz items missed; 4 to 6 Wrong. Use Glossary and Outlines to locate the content of each item scored wrong for review and study. 7 to 9 (or more) Wrong. Take or retake Studies 1-5 and Exercises 1-5, then retake the Logic Quiz.

- In logic, standard propositions are distinguished from nonstandard propositions according to the differences in quantity and quality.
- The Law of Identity holds that every sentence can be true or false.
- The Law of Excluded Middle states that all third parties are excluded in arbitration cases.
- Deductive argument has the following form: "If this is true, that is true: now that is true, therefore this is true."
- All deductive arguments are either probable or improbable.
- A proposition is the meaning of any complete sentence.
- The following are contradictories: Some persons are liars. Some persons are not liars.
- The following are contradictories: No politician is trustworthy. All politicians are trustworthy.
- The following are subcontraries: You ought to tell the truth. You ought not tell the truth.
- The conversion of "Most lawyers are not honest" yields the valid converse: "Most honest people are not lawyers."
- The contradictory of "All men are mortal" is "No men are immortal."
- The relation in "If 4 is less than 5, and 5 is less than 6; then 4 is less than 6" is a symmetrical relation.
- The propositions in arguments that begin with "all" or "no" or "none" are known as major premises.
- The minor premise of an argument is one that begins with "some" as in "Some lawyers are honest."
- An axiom is defined as a theorem that has been proven true.
- Theorems are the assumptions of a system of thought or body of knowledge.
- An enthymeme is a special type of inductive argument.
- From "A implies B" and the denial of A, we can validly deduce the denial of B.
- From "A implies B" and the assertion of B, we can validly deduce the assertion of A.
- This argument is invalid: "If no men are immortal, and Socrates is a man; then it follows that Socrates is mortal."
- The denial of a conjunction of propositions, "not (A and B)," logically implies a conjunction of the denial of each component, "not A and not B."
- The denial of a disjunction of propositions, "not (A or B)" is logically equivalent to a disjunction of the denial of each component, "not A or not B."
- An implication, "If A, then B," is logically equivalent to the implication "If B then A."
- This argument form is valid: All X are Z,
*and*All Y are Z,*Therefore*, All X are Y. - This argument is valid: If this beaker contains acid, it will turn litmus paper red. It turned red! Therefore, this beaker contains acid.

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