The reader of this book should know that we inquire into and speculate on
the teachings of our religion for two reasons: first, to find out for ourselves what
we have learned as imparted knowledge from the prophets of God; and
secondly, to be able to refute anyone who argues against us concerning
anything to do with our religion. Our Lord has instructed us in all we need to
know about the teachings of our religion through the agency of his prophets,
having first confirmed by signs and miracles that they possessed the gift of
prophecy. He commanded us to believe those teachings and keep them in mind.
He also informed us that, when we engage in speculation and inquiry, true and
complete inquiry will in every instance agree with what he has already told us
through the words of his messengers; and he has given us an assurance that
infidels will never be able to offer proof nor sceptics valid arguments against our
religion. ...[1
    In this way we engage in speculation and inquiry, so as to make our own what
our Lord has taught us by way of imparted knowledge. This inevitably raises a
point which we must now consider. It may be asked: 'If the teachings of religion
can be discovered by correct inquiry and speculation, as our Lord has informed
us, what prompted his wisdom to transmit them to us through prophecy and to
confirm them by visible, miraculous proofs, rather than by rational
demonstrations?' To this question, with God's help, we will give a complete
answer. We say: God in his wisdom knew that the conclusions achieved by skill
in reasoning can only be reached after the lapse of a certain interval of time. If,
therefore, he had left us to depend on such conclusions for our religious
knowledge, we would have remained for a time without religion, till the process
of reasoning had been completed and our labour had come to an end. It is
possible that many of us wQuld never have completed the process because of our
intellectual deficiencies, nor finished the work on account of impatience. Or
doubts could have overwhelmed us, confusing and hindering us. That is why
God saved us quickly from all these troubles by sending us his Messenger
[Moses] through whom he transmitted the truths directly to us, and before our
very eyes he confirmed those truths with signs and proofs which doubt could not
assail and which we could not possibly reject, as Scripture says: 'You yourselves
have seen that I talked with you from heaven' (Exod. 20: 19). He spoke to his
Messenger in our presence, and made it an obligation to believe his Messenger
for ever, as Scripture says: 'So that the people may hear when I speak to you,
and may also believe you for ever' (Exod. 19:9). [2
     Thus we were obliged at once to accept the teachings of religion, together
with all that they implied, because they had been verified by the testimony of
the senses. (We are also obliged to accept them on the grounds that they have
been passed on to us fully authenticated by reliable tradition, as we shall
explain later.) But God commanded us to take our time with our rational
inquiries till we should arrive by argument at the truth of religion, and not to
abandon our quest till we have found convincing arguments in favour of it and
are compelled to believe God's revelation by what our eyes have seen and our
ears heard. In the case of some of us our inquiries may take a long time before
they are completed, but that should not worry us; no one prevented by any
hindrance from pursuing his investigations is left without religious guidance.
Even women and children and those with no aptitude for speculation can attain
to a complete religion, for all men are on an equal footing as far as knowledge
derived from the senses is concerned. Praised be God who in his wisdom ordered
things thus! This is why you often find in the Torah the women and the children
included with the fathers when signs and miracles are mentioned. [3
    To make this matter clearer we could compare it to the case of a man who out
of a sum of 1,000 dirhems distributes the following: to five men, 20 dirhems
each; to six men 16 2⁄3; dirhems each; to seven men 14 2⁄7 ; dirhems each; to eight
men 12 ½ dirhems each; to nine men 11 1⁄9; dirhems each. He now wishes to let his
friends know quickly how much money he has left, so he tells them that the
remainder amounts to 500 dirhems and proves his statement by weighing the
money. When he has quickly weighed it and found it to be 500 dirhems, they are
obliged to believe what he told them. They can now take as long as they like to
reach the same conclusion by calculation, each according to his ability and
understanding and the difficulties he may encounter. Or we could compare the
matter to the case of a man who, on being told of an illness accompanied by
certain pathological conditions, immediately identifies what the illness is from
some characteristic symptom, and whose diagnosis is later confirmed by
someone investigating the illness by means of an exhaustive inquiry. [4