If the proof of Allah’s existence is so simple, then why doesn’t the world convert to Islam?

From: http://www.defending-islam.com/page373.html

If the proof of Allah’s existence is so simple, then why doesn’t the world convert to Islam?
(Original Source: http://sunnianswers.wordpress.com/2008/06/11/q-a-if-the-proof-of-allahs-existence-is-so-simple-then-why-doesnt-the-world-convert-to-islam/)
Question: If it is that simple, and the proof so clear, why does not the whole world convert to Islam?
Answer: Because obvious proofs do not cause acceptance. You know, I struggled with another version of the proof in “Foundations of the Religion” when I had first converted to Islam. I needed them, because I knew I would be facing a wave of mockery from my own people due to my conversion. I wanted proofs that were based on commonly accepted premises to fight back to show that I was right. I even thought that if I could prove my beliefs logically based on common premises, the whole world would quickly become Muslim, and that is why I was euphoric the first time I learned them. Now I know that humans are far from rational, and the fact that the world didn’t become Muslim was a clear proof for me that no one believes unless Allah has willed it:
“وَاللَّهُ خَلَقَكُمْ وَمَا تَعْمَلُونَ”
Meaning: “Allah created you and what you do.” (As-Saaffaat. 96)

My experience makes it easy to accept that people like Abu Talib or other idolaters like Abu Lahab, knowing the truth by having seen miracles in front of their eyes, still did not accept Islam. It is mentioned in tafsiir books that when this was revealed:
إِنْ هُوَ إِلا ذِكْرٌ لِلْعَالَمِينَ () لِمَنْ شَاءَ مِنْكُمْ أَنْ يَسْتَقِيمَ
Meaning: “Verily this is a warning to the worlds, so the one who wills will take the path of fearing and obeying Allah” (Al-Kawthar, 27-28).

Then the idolaters said, “so it is up to us, if we want, we will.” So Allah revealed:
وَمَا تَشَاءُونَ إِلا أَنْ يَشَاءَ اللَّهُ رَبُّ الْعَالَمِينَ
Meaning: “You do not will anything unless Allah has willed it.”

The first version I learned of this proof used simple math, and I ventured out to present it when challenged about my conversion. The problem was that I had not understood some of the underlying assumptions of that version and a mathematician had a field day with me due to my ignorance. Bruised and beaten, I set out to understand it properly, and to learn how to present it in a way that anybody can understand, and without having complicated ideas in the argument or underlying the argument.
I had my “revenge,” by the Grace of Allah when I faced a hypocrite that used to attend my lessons pretending to be Muslim for marriage purposes. He had a degree in math and physics. One day I announced, “I can prove that Allah exists, and that the Islamic belief in God is correct.” He said mockingly, “O really…, how so?” He was probably expecting an argument based on design, or contingency, and had his arsenal ready. When I explained to him the proof he made an attempt or two to throw me off, but because the argument is simple and clear, it was easy to silence him, by the Grace of Allah. He stood up and said, “I will think about it, I take it as a challenge!” He never came back to my lessons, and avoided me like the plague after that. Subhan Allah, how can someone with a fragment of good in their heart be annoyed by a proof that shows that the Creator exists?

In another quite different instance I was teaching a person who had converted and was taking classes so that he could marry a Muslim girl. Whenever I receive converts I fear they might not be convinced, but just going along to “get the girl,” or some other reason, so if there is time I will present the above proof. One time I had a gentleman with a Master’s Degree in aeronautical engineering from a prestigious university. When I presented the proof he actually started crying, and even explaining it to others. For the most part however, whenever I use it on a non-Muslim I get a nodding, “yes you are right,” and then…. nothing. As if I had told them something very ordinary, that has no implications. That is why I see these proofs mainly as defense systems, not change agents, because most people change only for emotional reasons, not logical reasons. These proofs are important for preventing deviants to affect Muslims by answering their attacks. They are also important to help someone affected by doubts.
Authored by Shaykh Abu

Blogger Comment:
If man can can feel his body with my hands and can see himself in the mirror he is existing. If he came from tow parents that they came from another and so forth there is two pairs that started humanity. Since there is no strong proof that they created themselves or found from nothing they were created. If the creator decided at anytime to reveal himself we have to listen to him and examine his message. In the above three verses: He would declare that his the creator and what we create is part of his creation, and he would reveal his message as a creator and those who follow are those who seeking the truth that is why those are the only ones who are guided. It is a simple and clear mathematics like 1 + 1 = 2. If you read the Quran to find the truth you will be guided and if you read it to defeat it you will go astray. There is no proof that because there are non-Muslims that Islam is false. The thing we can say if you read the Quran with open heart and mind the likelihood to be guided is very high.