Deduction

Deduction is the process of leading from statement to statement following the logical consequences of each statement and its relation to succeeding statements. Deductive arguments typically depend on syllogisms and enthymemes.

In order for the conclusions reached by deduction to be sound,

1. all of the premises must be true
2. the argument must be valid

A premise is considered true if it conforms to reality. An argument is valid if the conclusion logically follows from the premises. For instance, the following syllogism is false:

Major Premise: All parents are fathers.
Minor Premise: Mary is a parent.
Conclusion: Therefore, Mary is a father.

The syllogism is false because the major premise is false. Not all parents are fathers.

The following syllogism is invalid

Major Premise: All fathers are parents.
Minor Premise: Mary is a parent.
Conclusion: Therefore, Mary is a father.

The syllogism is invalid because the major premise does not logically support the conclusion. While all fathers are parents, not all parents are fathers.

Works Cited

Barnet, Sylvia and Hugo Bedau. Critical Thinking, Reading, and Writing: A Critical Guide to Argument. 3rd ed. Boston: Bedford St. Martin's, 1999.

ENGL1010 Composition I