As a person who likes to study the apologetics and epistemologies of many religions, they each basically say that, and that they've experienced it (a witness) and that therefore they now know their belief system is the one outside of or more than the philosophies of man.**

As for me (I know you didn't ask:), I'd say I, along with Jordan, am also on the path. I am a truth seeker. In the study of religion, orthopraxy is correct conduct, both ethical and liturgical, as opposed to faith or belief. Orthopraxy is in contrast with orthodoxy, which emphasizes correct belief, the practice of "correct" rituals, etc.

So I am Orthopraxy, not Orthodoxy. I keep the law of chastity, word of wisdom, tithe, rarely watch worse than pg-13, serve, keep "the sabbath day", am honest, etc. I believe in correct conduct (for secular reasons), but I am as critically thinking as Jordan is (but on my own lower IQ level) on religious "doctrines". And as a parent, hypothetically, if push came to shove and I had to choose between only one or the other, I'd rather my kids have good behavior than correct beliefs.

Anyway, its practically impossible for a believing Muslim to doubt his faith because of his experiential witnesses within Islam. But really he is without knowing it, expressing confidence in himself and his ability to decipher between his own feelings, conditioning, and biases from feelings that are an actual witness from Allah that Islam is true. Same goes for everyone I suppose.

** https://youtu.be/ULucaHFYKPk?t=76