What does “non-real” mean in the definition of ḥusn al-taʿlīl?

The Dialectical Method and Elegant Causal Attribution: Proof and Four Modes of Ḥusn al-Taʿlīl

• The quality is unestablished even if the cause is real
• The attributed cause is not the actual cause of the event
• Omitting the causal noun but retaining the quality
• Figuratively wording the real cause without changing the relation