Your God is one God. There is no God but He. He is the Most Gracious, the Ever Merciful. Indeed, in the creation of the heavens and the earth; in the alternation of night and day; in the ships that sail the ocean with cargoes beneficial; in the water, Allah sends down from the clouds and with which He revives the dead earth and with which He dispersed over it all kinds of animals; in the movement of winds and in the clouds that are driven between the earth and the sky surely are signs for men of understanding. (2:163-164)

It is generally believed in our religious circles that the teachings and directives of Islam only appeal to our emotions and sentiments; they do not address our intellect and as such they have to be accepted and obeyed without being inquisitive about the logic and philosophy behind them. The Asharites, the largest school of Muslim dialectics, also hold this view point.
This view seems to contradict the Qur’an. The Qur’an explicitly states that all Islamic beliefs and directives have sound reasons behind their inception and that they conform to the highest possible standard of rationality. Consequently, whenever the Qur’an urges man to accept certain dogmas, it cites arguments to substantiate its claims. It warns those who evade and ignore its calls to use their faculty of reasoning instead of being a slave to emotions like hate and prejudice. In fact, a little deliberation shows that it wants us to obey certain religious commandments just because the Almighty has blessed us with the faculty of reasoning. Thus, a perfectly healthy person who is insane has been relieved from all religious responsibilities by Islam. In spite of being fit and healthy in all other respects, he has not been asked to say his prayer or fast, nor is he liable for punishment for any crime which he commits.
An important point which must be understood in this regard is that we are required to accept certain realities without observing them because their existence can logically be deduced. For example, we are not able to see God; the Day of Judgement too is as yet concealed from our eyes, nor have we witnessed Gabriel revealing the Divine Message to the Prophet (sws). Yet, we believe in all these because present in the Qur’an, in our own intuition and in every phenomenon of nature are signs which testify that these realities are rationally proven facts. It is highly irrational on the part of man to demand a visual display of realities which though, unseen can be understood rationally. It is his misfortune that on the one hand when he delves deep in the domains of science he accepts certain realities which cannot be observed but the existence of which can be proven by other means, and on the other hand he adopts a completely different attitude when he comes across certain metaphysical realities of life.
In other words, some realities upon which the Qur’an asks us to believe are certainly beyond the perception of senses but not beyond the perception of reason. Just as footsteps on sand testify beyond doubt that someone has gone past, likewise writ large on every created matter of this universe is that someone else also has just gone past and left an indelible expression of his own existence.