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Dr. Jay
VerLinden
Communication
Department
College of Arts, Humanities
and Social Sciences
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Argumentation and Critical Thinking Tutorial

FORMAL LOGICAL STRUCTURE
REVIEW

This page reviews the fundamental characteristics of logical arguments. It does not contain explanations for any of the concepts, so you should be sure to read some material on formal validity before you take the tests.

A SYLLOGISM is an argument that has a major premise, minor premise, and conclusion and arrives at an absolutely certain concslusion, assuming the premises are true.

An ENTHYMEME is an argument similar to a syllogism, but may be missing one or more parts OR arrive at an uncertain conclusion, OR both.

The major premise is a statement of a general or universal nature.

The minor premise is a statement regarding a particular case, related to the subject of the major premise.

The conclusion is the inevitable result of accepting the major and mionr premises.

The three types of arguments are categorical, disjunctive, and conditional.

CATEGORICAL arguments have major premises that place items into categories. (All A's are B.)

DISJUNCTIVE arguments have major premises that identify two or more alternatives. (Either A or B)

CONDITIONAL arguments have major premises that establish what will happen if certain conditions exist. Conditional arguments are also known as hypothetical arguments. (If A, then B.) The "If" phrase is called the ANTECEDENT. The "then" phrase is called the CONSEQUENT.

EXAMPLES OF FORMAL STRUCTURE

 CATEGORICAL

DISJUNCTIVE

CONDITIONAL

Major Premise

All A's are B's

Either A or B

If A, then B

Minor Premise

C is an A

Accept A

Affirm A

Conclusion

C is a B

Reject B

Affirm B

 CATEGORICAL

DISJUNCTIVE

CONDITIONAL

Major Premise

No A's are B's

Either A or B

If A, then B

Minor Premise

C is an A

Reject A

Deny B

Conclusion

C is not a B

Accept B

Deny A

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