There are many witnesses to aliens landing on earth. Perhaps aliens are the ID'r?
Weigh the evidence.
Moses claimed he saw a bush that didn't burn and other similar oddities. THe Hebrews weighed the evidence and believed him enough to follow him to the desert. You apparently would have stayed and made clay bricks the rest of your life.
We all weigh the evidence of witnesses and decide whether it meets are requirements to believe. Everything you know is based on witnesses.