«الممكنة الخاصة»
Special possibility.
«وهي التي حكم فيها بارتفاع الضرورة المطلقة عن جانبي الوجود والعدم جميعا»
It is a proposition that denies unrestricted necessity on both sides, existence and nonexistence.
General possibility denies the necessity of the opposite and can therefore include necessary propositions. Special possibility goes further by denying necessity in either direction.
The predicate's presence is not essential and its absence is not essential either. The two opposed outcomes are open in the sense of special possibility.