I just read this question and I have a followup question. The top answer says,
If there was a clearcut incontrovertible proof that was acceptable to everybody (like say a mathematical proof) then this life wouldn't be a test...
Imagine that there are several different faiths that make a claim similar to the quote above. Lets put Islam in that group of faiths. As a non-believer, I can choose one or none. How should an atheist like myself approach multiple religions making the same claim? I'm only interested in the truth, and my mind is open to being changed by whatever makes the most sense to me.
Second question: I have had people (from a different faith, not Islam) tell me that receiving a revelation from their god takes time, meaning that it won't happen instantaneously. It takes time, but will happen eventually if I pursue their god honestly and sincerely. Is the same true of Islam? If so, how long should I try each faith in that category before I give up and move to the next one?