عدمُ العِلْمِ بِالْمُقَيَّدَاتِ
Not knowing the details that would provide a qualification.
A speaker may know an event occurred while lacking knowledge of its exact time, place or participant. Inventing such information would be an unsupported assertion. “A traveller arrived” can be informative even without the traveller’s identity.
Omitting unknown details differs from intentionally withholding known details; these acts have different motives. A statement can still be useful when its available, relevant content is presented accurately.