We believe that Allah has endowed us with the faculty of the intellect ('aql), and that He has ordered us to ponder over His Creation, nothing with care the signs of His power and His Glory throughout the entire universe as well as ourselves. It is stated in the Qur'an:
We shall show them Our signs on the horizons and in themselves, till it is clear to them that it is the Truth. (41;53)
Allah has shown His disapproved of those who blindly follow the ways of those who were before them:
They say: "No, but we will follow such things as we found our father doing." What! And if their fathers had no understanding of anything. (2;170)
and he has shown his dislike for those who follow nothing but their own personal whims:
They follow naught but an opinion.
Indeed, our intellect forces us to reflect upon Creation so as to know the Creator of the universe, just as it makes it necessary for us to examine the claims of someone to prophethood and to consider the truth of his miracles. It is not correct to accept the ideas of someone without criticism, even if that person has the gift of great knowledge or holds an esteemed position.
The reason that the Quran has urged us to reflect upon Creation and to study the natural world and acquire knowledge is so that it may confirm in us mankind's instinctual freedom of thought upon which all sages are in agreement, in other the power of human understanding and thinking may be so enlightened that it may fulfill the function for which it was created.
Thus it is wrong for a man to neglect the fundamentals of his faith and to put confidence in what his instructors or other persons have said to him. On the Contrary, it is necessary for him, on account of his natural intellegence as confirmed in the Qur'an, to search for, examine and come to clear understanding of the fundamentals of his religion (usul ad-din), Prophecy (nubuwwah), the Imamate (imamah) and the Resurrection (ma'ad). One who follows the dictates of his forbears or any other person in these matters has, in truth, committed an error and has wandered from the straight path, and there can be no excuse for such an action.
In short, there are two points:
(a) that it is necessary to examine and understand the fundamentals our beliefs and not to follow what anyone else might say.
(b) that this is a requirement that stems from reason, and not one that we must accept the religion (i.e. such knowledge is not only to be gained from religious texts, even if, as we have seen, it is confirmed there, but it is also to be obtained through the exercise of the intellect). The meaning of a requirement that stems from reason is that reason enjoins us to acquire such knowledge and to examine these matters for ourselves.
