You can see viruses under a microscope
you can do experiments to prove what is IN air and that it exists (don't believe me? Go into a sealed room and get somebody to suck all the air out. See what happens..
Satellites show that the Earth is of a round shape, and the position of the sun in the sky as well as astronomers and scientists have shown that the Earth revolves around the sun. There is ample evidence to support these FACTS. There is no evidence of a god, only faith...
Next.....
Let's assume you know nothing about these facts. Don't you have to search for answers in all of these examples? You have to at least make an effort to discover. When it comes to air, viruses, the Earth, and the Sun you have to look for something that you may not have already known existed. It has to be discovered. Curiosity caused us to discover them. If you have no curiosity for why we're here then you won't discover anything.
The problem with your argument is that you believe nobody ever saw evidence that he existed..which isn't true because those who wrote some of the books of the Bible saw actual evidence that God exists. The parting of the Red Sea, the writing of the 10 Commandments, the resurrection of Christ. They saw it with their own eyes.