I don’t know who would like to read all this but I like it. This is how al ghazali dealt with doubt.
“In this and similar cases of sense-perception the sense as judge forms his judgements, but another judge, the intellect, shows him repeatedly to be wrong; and the charge of falsity cannot be rebutted.
To this I said: `My reliance on sense-perception also has been destroyed. Perhaps only those intellectual truths which are first principles (or derived from first principles) are to be relied upon, such as the assertion that ten are more than three, that the same thing cannot be both affirmed and denied at one time, that one thing is not both generated in time and eternal, nor both existent and non-existent, nor both necessary and impossible’.
Sense-perception replied: `Do you not expect that your reliance on intellectual truths will fare like your reliance on sense-perception? You used to trust in me; then along came the intellect judge and proved me wrong; if it were not for the intellect judge you would have continued to regard me as true. Perhaps behind intellectual apprehension there is another judge who, if he manifests himself, will show the falsity of intellect in its judging, just as, when intellect manifested itself, it showed the falsity of sense in its judging. The fact that such a supra-intellectual apprehension has not manifested itself is no proof that it is impossible’.
My ego hesitated a little about the reply to that, and sense-perception heightened the difficulty by referring to dreams. `Do you not see’, it said, `how, when you are asleep, you believe things and imagine circumstances, holding them to be stable and enduring, and, so long as you are in that dream-condition, have no doubts about them? And is it not the case that when you awake you know that all you have imagined and believed is unfounded and ineffectual? Why then are you confident that all your waking beliefs, whether from sense or intellect, are genuine? They are true in respect of your present state; but it is possible that a state will come upon you whose relation to your waking consciousness is analogous to the relation of the latter to dreaming. In comparison with this state your waking consciousness would be like dreaming! When you have entered into this state, you will be certain that all the suppositions of your intellect are empty imaginings. It may be that that state is what the Sufis claim as their special `state’ (sc. mystic union or ecstasy), for they consider that in their `states’ (or ecstasies), which occur when they have withdrawn into themselves and are absent from their senses, they witness states (or circumstances) which do not tally with these principles of the intellect. Perhaps that `state’ is. death; for the Messenger of God (God bless and preserve him) says: `The people are dreaming; when they die, they become awake’. So perhaps life in this world is a dream by comparison with the world to come; and when a man dies, things come to appear differently to him from what he now beholds, and at the same time the words are addressed to him: `We have taken off thee thy covering, and thy sight today is sharp’ (Q. 50, 21).
When these thoughts had occurred to me and penetrated my being, I tried to find some way of treating my unhealthy condition; but it was not easy. Such ideas can only be repelled by demonstration; but a demonstration requires a knowledge of first principles; since this is not admitted, however, it is impossible to make the demonstration. The disease was baffling, and lasted almost two months, during which I was a sceptic in fact though not in theory nor in outward expression. At length God cured me of the malady;”