إن كان زيد إنسانا كان حيوانا لكنه إنسان.
If Zayd is human, he is an animal; but he is human.
The antecedent is “Zayd is human”; the consequent is “Zayd is an animal.” Affirming the antecedent licenses the conclusion that he is an animal.
This differs from the invalid move: “If Zayd is human he is an animal; Zayd is an animal; therefore he must be human.” Other kinds of animal exist, so that conclusion does not follow.
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Proof: Syllogism, Induction, Analogy and the Four Figures
إن كان زيد إنسانا كان حيوانا لكنه إنسان.
If Zayd is human, he is an animal; but he is human.
The antecedent is “Zayd is human”; the consequent is “Zayd is an animal.” Affirming the antecedent licenses the conclusion that he is an animal.
This differs from the invalid move: “If Zayd is human he is an animal; Zayd is an animal; therefore he must be human.” Other kinds of animal exist, so that conclusion does not follow.