xenophon41 said it very well.
Eh, there are a number of assumptions here that really don’t matter. Faith is not usually held up to “rigor” (although there are many believers who espouse that there are degrees of faithfulness, i.e. that insist on strict adherence to generally accepted tenets and rituals; I suppose one could regard such adherents as “rigorous” within their worship, but usually they are called fervent or devoted or extremists). Faith defies logic; it works outside of logic. I find it difficult in the extreme to believe that the educated, intelligent people here have obtained adulthood and not discovered this for themselves. Even if one is not faithful, does not believe in any type of God and espouses atheism, that does not (or it should not) imply that one cannot comprehend that one’s worldview is not the same for everyone (or anyone) else–which is why I find this thread disingenuous and the specter of trolling (the “gotcha”) has been raised by several posters. If God is not real to you, how does that make God not real, period?
Here’s something to think about: your memories and your dreams are real, in that they actually happened–I don’t mean the actual concrete event that happened in the past, but your memory of it (whatever “it” may be). Your dreams are also real, in that they existed in your brain for whatever cycles of REM sleep you had that night (I am assuming you remember your dreams). But there is no concrete evidence of your dreams. There may well be no physical artifact that proves your memory. But are they any less real to you?
Put another way: You shared a past event with a sibling or a friend. Time passes, several years, and you come to find out that your memory and her memory of the same event differ greatly. Is one person right and another wrong? Barring any contemporaneous record or “proof”, neither of you is wrong–but neither of you is right, either. Funny how people understand this and accept it, but bring God into it and confusion reigns.
I am not saying God is a dream or a memory: I am drawing an analogy to assist in communication. Barring developmental delays, brain disorders or psychiatric issues, we here are all able to grasp the abstract. Faith (that is, believing in God or “God” if that makes people more comfortable) is abstract. So is love–not just divine love, but human love itself. It has concrete manifestations, but “love” itself is not a separate, measurable entity. If you can understand the concept of love, you can understand the concept of God/faith.