Allah T’ala says in the Holy Quran:


وَالَّذِينَ كَذَّبُواْ بِآيَاتِنَا صُمٌّ وَبُكْمٌ فِي الظُّلُمَاتِ مَن يَشَإِ اللّهُ يُضْلِلْهُ وَمَن يَشَأْ يَجْعَلْهُ عَلَى صِرَاطٍ مُّسْتَقِيمٍ﴿6:39﴾


(6:39) Those who gave the lie to Our signs are deaf, dumb and blunder about in darkness. Allah causes whomsoever He wills to stray in error, and sets whomsoever He wills on the straight way.'  



The universe and what it contains are signs of God, the Creator. . One can reflect on organic structure of any animal and notice how its instinctive urges are in complete conformity with its natural requirements. How wonderfully adequate are the arrangements for providing every animal with nourishment; how marvellously well-determined are the limits within which it lives; how tremendously efficient is the system under which each living creature is protected, provided for, looked after and directed towards self-fulfillment; how strictly each one is fitted into the framework of the discipline devised for it, and how smooth is the operation of the whole system of birth, procreation and death. Were one to reflect on this alone from among the innumerable signs of God, one would perceive fully how true the teachings of the Prophet (peace he on him) are concerning the Oneness of God and His Attributes.


We see that many people mindlessly ignore countless signs of God which are scattered all over the universe, and ignore even such signs which are manifest in human beings and animals. It is little wonder, then, that they derive no lesson from all these signs. There are many who study zoology, botany, biology, geology, astronomy, physiology, anatomy and other branches of science. Others study history, archaeology and sociology. During the course of such studies they come across many signs of God which, if they had cared to look at them in an unbiased perspective, might fill their hearts with faith. But since they commence their studies with a bias, and are actuated only by the desire to acquire earthly advantages, they fail to discover the signs which could lead them to the Truth. On the contrary, each of those very signs of God contributes to pushing them towards atheism, materialism and naturalism. At the same time, the world is not empty of those truly wise ones who view the universe with open eyes. For them even the most ordinary phenomenon of the universe directs them to God.

(Tafseer from Tafheemul Quran)