I believe that there are many things that we do not know and as we have never seen them, because they do not exist for us. From the very moment that the object, person or situation I name it, it makes presence in me, from that moment the wonderful experience of knowledge begins. I know, because I see or I have heard it! Interesting topic
Yeah we can't know in truth what we can't demonstrate in reality. Technology helps to record things to help give accounts of what happened. But we end up trusting a whole lot.