True, Sharon, good point.
What I mentioned is only the most common reason for that belief, and most other religious convictions. Others merely acquiesce to the culture of their regional faith.
But faith is not proof of anything being true, no matter how many declare the same belief. Belief systems rose amid the absence of facts -which is to say, real understanding; and concordantly, religiosity tends to be inversely proportional to the amount of fact-based education.
The truth is what the facts are. An unsupported claim is no more valid than one proven wrong.