It is normally claimed that concept of God is in the very nature of human beings, as you also seem to have implied in one of your answers, if this is so, then why does not everyone believe in God?
The fact that a particular concept or value is entailed in the very nature of man does not imply that man cannot deviate from that particular value or concept. On the contrary, the external environment of a particular person as well as his own positive or negative attitude toward these values and concepts may strengthen or weaken the impulses of these values and concepts inherent in man's nature.
Take, for instance, the example of cleanness. Keeping oneself as well as one's environment clean is, indeed, one of the natural inclinations of man, yet with persistent deviation from this natural inclination, the light of this invaluable flame, which God has lit within man's heart may start to fade and, ultimately, extinguish. At that time, man loses all sense of dislike for uncleanness. This is very effectively portrayed in one of the letters that I received, some time back. In this letter, a couple who had recently converted to Islam, wrote:
My question is that in India it is customary for Husband/Wife to use the other spouses' urine for some applications like washing the hair with it before shower. In some instances, spouses drink drops of their partners' urine for health...
As is obvious, man can easily weaken the impulses of even these naturally induced values and concepts by persistently avoiding to abide by them or under the negative influence of his external environment. The same is the case of all other values and concepts, which are entailed in the nature of human beings. More easily comprehensible examples of man's deviations from the concepts and values entailed in his nature are his telling a lie, or his being unjust to his fellow human beings, or his behaving in an unkind manner toward those who are weaker than him etc. Even though all these actions are contrary to the values and concepts entailed in the very nature of man, yet we know that man can so easily silence his screaming conscience and opt to tread a path, which takes him on route to fighting and, ultimately, killing the 'goodness' inherent in his nature.
Thus, even though the concept of a deity is entailed within man's nature, yet by persistently avoiding to accept this concept or by satisfying oneself with more 'fancy' and 'fashionable' ideas or merely by being under the influence of one's external environment, one may weaken the impulse of believing in God to the extent that one, sometimes, reaches the level of even rejecting the idea of the existence of a deity.
I hope this helps.April 6, 2001
Answer published by Moiz Amjad