I would say that we cannot prove them to be the truth so they are not facts, but we can still know them to be true because all knowledge is not based on facts we can prove. That said, we should never claim they are true and expect others to believe they are true because we cannot prove they are true since claims require proof. But we can still say we know they are true because certitude is an inner knowing, and nobody can take our certitude away from us because it isn't their to take.
knowledge;
1. facts, information, and skills acquired by a person through experience or education; the theoretical or practical understanding of a subject.
2. awareness or familiarity gained by experience of a fact or situation.
knowledge means - Google Search