The inference can have a valid first-figure form even if one of its premises is false or unwarranted. Its form is sound as an inference pattern but its matter is unsound.
Example:
Every existent is a body.
Every body is spatial.
Therefore every existent is spatial.
The universal arrangement is formally valid. Yet the first premise is not accepted in the classical discussion of non-bodily entities. The conclusion is not established as knowledge merely by giving the inference a valid shape.
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Sophistical Syllogism: Illusory Premises, Deceptive Resemblances and Fallacies
The inference can have a valid first-figure form even if one of its premises is false or unwarranted. Its form is sound as an inference pattern but its matter is unsound.
Example:
Every existent is a body.
Every body is spatial.
Therefore every existent is spatial.
The universal arrangement is formally valid. Yet the first premise is not accepted in the classical discussion of non-bodily entities. The conclusion is not established as knowledge merely by giving the inference a valid shape.