LessonsSemantic Fallacies: Defects of Matter, Form, and PredicationQuiz

Contrast the fallacy with a valid first-figure syllogism:
كل إنسان ناطق
Every human is rational.
كل ناطق حيوان
Every rational being is an animal.
فكل إنسان حيوان
Therefore every human is an animal.

The middle term, rational, is used with the same logical force in both premises. The minor is affirmative, the major universal, and the first-figure requirements are satisfied.

Adding or removing a qualification is therefore not a harmless verbal change. It may change the premise and the inference itself.

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A sound syllogism keeps its middle term fixed

Semantic Fallacies: Defects of Matter, Form, and Predication

Contrast the fallacy with a valid first-figure syllogism:
كل إنسان ناطق
Every human is rational.
كل ناطق حيوان
Every rational being is an animal.
فكل إنسان حيوان
Therefore every human is an animal.

The middle term, rational, is used with the same logical force in both premises. The minor is affirmative, the major universal, and the first-figure requirements are satisfied.

Adding or removing a qualification is therefore not a harmless verbal change. It may change the premise and the inference itself.