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Syllogism Page

An Example of a Deductive Categorical Syllogism

Deals with category of things.

Major Premise:               All politicians are propagandists 

    Minor Premise:            All propagandists are unethical

        Conclusion                All politicians are unethical

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An Example of a Conditional Syllogism

Deals with a category of things under a specific condition.

Major Premise:            If any one eats that poison he/she will die.

    Minor Premise:        Sam ate that poison.

        Conclusion:           Sam will die or is dead. 

Why the Syllogism Does Not Work Very Well in Informal Arguments.

For years the deductive syllogism has been considered the structure for sound reasoning. However, this structure does not work well as a structure for an argument, for the following reasons.

• We seldom argue about things which can always be included in the broad categories which make up the premises of a syllogism.

• The conclusion of a deductive syllogism adds nothing new to the information included in the premises. 

• If we know the premises are true, the conclusion must follow absolutely.  In example one, the premises are hardly true, but the structure of the argument is sound. 

• In an argument, we seldom have the luxury of being able to proceed from absolutely true and all inclusive premises. 

• Most important, in an argument, we attempt to use something we know in order to learn something we did not know before. 

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