What we believe

you become what you focus your attention on.

One does not need to believe anything.

When you cross a road you need to know that it is safe to do so.  Believing that you can cross the road safely is not smart.  So what do we do?  We use out life experience if we have any.  We use our sensors and we may use instruments,  eg mirror, hearing aid.  We choose a location that provides sight distance.