The humans, unlike the rest of Allah's living creatures, use their mind to think and decide.
A person who did not know about Islam would either follow it by nature since every human being thinking and observing this world, at some point(s) of time, can believe in the existence of only one Creator, or the person can be following the religious beliefs of his/her parents or the people around him/her - or can be an atheist.
The topic of fate is very interesting. The Islamic view of fate, as explained in Islam Q&A, is as follows:
The belief of Ahl al-Sunnah wa'l-Jamaa'ah is that a person has freedom of will, and hence he will be rewarded or punished. But his will is subject to the will of Allaah, and nothing can take place in the universe that is not willed by Allaah.
What some people say, that we have the choice to follow whatever path we want but at the end of this path you will find what Allaah has decreed for you, is a correct view. Allaah says (interpretation of the meaning):
“Verily, We showed him the way, whether he be grateful or ungrateful” [al-Insaan 76:3]“And shown him the two ways (good and evil)?” [al-Balad 90:10]
“And say: “The truth is from your Lord.” Then whosoever wills, let him believe; and whosoever wills, let him disbelieve” [al-Kahf 18:29]
Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) said, explaining the view of Ahl al-Sunnah with regard to man’s deeds:
People act in a real sense, and Allaah is the Creator of their actions. A person may be a believer or a kaafir, righteous or immoral, he may pray and fast. People have control over their actions, and they have their own will, and Allaah is the Creator of their control and will, as Allaah says (interpretation of the meaning):
“To whomsoever among you who wills to walk straight.
And you cannot will unless (it be) that Allaah wills the Lord of the ‘Aalameen (mankind, jinn and all that exists)” [al-Takweer 81:28-29]
The topic I am going to provoke your thinking into it is: why people either believe, disbelieve or wrongly believe in (not the same) god?
