Someone once said (I am not sure who or in what context): “For those who believe, no proof is necessary. For those who don't believe, no proof is possible.”
I think in most cases this is true. Many believers think just the existence of a book is proof that the words in it are the truth. On the other hand, a non-believer would not believe even if he met someone who claimed to be a God and performed multiple miracles to prove it - he would just accuse the person of being a magician and of performing tricks.
For example, in 1995, many idols of Hindu gods (particularly idols of Ganesha) started drinking (or absorbing) milk that was offered to them by devotees:
Ganesha drinking milk miracle - Wikipedia . At that time there were literally millions who witnessed this phenomenon which occurred world-wide from Delhi to London to HongKong to Sunnyvale with some say hundreds of idols, even those at some people's homes. Many TV networks made videos of this happening.
However, in the end everyone including the Indian government (which was a secular one at that time) debunked the phenomenon. Scientists came up with various theories like capillary effect or osmosis to explain the phenomenon. In time, the official videos posted by major networks like CNN and BBC mysteriously disappeared, only the ones made by believers remained (
http://www.milkmiracle.org or search youtube). After a few days, the phenomenon stopped happening.
The question is that if the 'miracle' can be explained so easily by capillary action or surface tension, why has nobody been able to reproduce it since? Of course, even an amateur magician can probably rig some idol with tubes or something and reproduce it, but no serious investigator has been able reproduce with a store-bought Hindu idol (readers should try their own experiments, if they want).
So are the videos made or posted by believers, evidence? Is the fact that non-believers (and non-magicians) have not been able reproduce the phenomenon, evidence?