Two negative premises, such as "No A is B" and "No B is C", yield
- A. the conclusion that no A is C
- B. the conclusion that all A are C
- C. no valid conclusion
- D. the conclusion that some A are C
Explanation
Nothing links A and C when both premises merely exclude, so A and C might overlap completely, partly or not at all. This is one of the standard rules of the syllogism: from two negatives nothing follows. It is a common trap because the pattern looks like a chain.
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