Why can “Ḥātim” designate another person in “I saw a Ḥātim today”?

Istiʿārah: Definition, Figurative Identification and the Linguistic–Intellectual Debate

• Because the person resembles the famously generous man and context permits it
• Because Ḥātim is literally a common noun for everyone
• Because there never was a historical referent
• Because “today” invariably entails falsehood