Premises:
Some teachers are poets.
Some calligraphers are teachers.
Both can be true while the poet-teachers and calligrapher-teachers are distinct people. “Some calligraphers are poets” then need not follow.
Two particular premises do not force their witnesses to be the same individuals. Hence the proposed endpoint relation may fail regardless of what figure the two premises superficially resemble.
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The Fourth Figure: Productive Conditions, Moods and Proofs
Premises:
Some teachers are poets.
Some calligraphers are teachers.
Both can be true while the poet-teachers and calligrapher-teachers are distinct people. “Some calligraphers are poets” then need not follow.
Two particular premises do not force their witnesses to be the same individuals. Hence the proposed endpoint relation may fail regardless of what figure the two premises superficially resemble.