Consider this invalid inference:
All cats are animals.
All dogs are animals.
Therefore all cats are dogs.
Both premises may be true while the conclusion is false. Sharing a broad predicate does not make the subjects identical: two different kinds can both fall within “animal.” The argument has the second-figure form but is not a valid syllogism.
Identifying a figure concerns where the terms occur. Establishing validity requires further conditions governing how the premises relate.
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The Second Figure: Conditions of Validity and Four Productive Moods
Consider this invalid inference:
All cats are animals.
All dogs are animals.
Therefore all cats are dogs.
Both premises may be true while the conclusion is false. Sharing a broad predicate does not make the subjects identical: two different kinds can both fall within “animal.” The argument has the second-figure form but is not a valid syllogism.
Identifying a figure concerns where the terms occur. Establishing validity requires further conditions governing how the premises relate.