To thee We sent the Scripture in truth, confirming the scripture that came before it, and guarding it in safety: so judge between them by what Allah hath revealed and follow not their vain desires, diverging from the Truth that hath come to thee. To each among you have We prescribed a Law and an Open Way. If Allah had so willed, He would have made you a single People, but (His Plan is) to test you in what He hath given you: so strive as in a race in all virtues. The goal of you all is to Allah; it is He that will show you the truth of the matters in which ye dispute. Q:5:48
This verse, in my opinion perhaps the most difficult verse in the entire Qur’an, indeed tells in a nutshell what belief in a Creator is and why it is so that the various believers do not come nearer to each other. The way of conduct and the open path refer to the relation between Allah swt and each individual of His creatures, but also between Allah and the entire community of men. Every person has his, her own relation with Allah, however, there also is a Scripture that not only addresses itself to the individual, but also to all those other people. Except for this Scripture Qur’an there are other scriptures, where communities other than the Islamic listen to. Therefor we may conclude: it is so simple, there is only one physical truth. Yet it is not simple, as man has received only a very limited view on this physical truth and has, however, obtained the right to make his own idea of it. So there is one truth and yet everybody has their own truth. Not is said here who precisely is correct. Not without reason Islam means peaceful surrender to God and man has received the needed tools from the Prophet, but also the option of choice. Precisely because we have only a limited view on the truth, there can never be compulsion in religion. The last Scripture the Qur’an contains the truth. Yet it may be so that other paths to this truth may be acceptable. And truly acceptable, not just second best. Allah knows truly in the end.
Then the second aspect is that discussions between believers and non-believers or otherwise-believers usually don’t lead to much result in the sense of convincing others of your being right. Islam has said: Allah decides whether a person believes and if so then what, or disbelieves. The separation of minds leads to different religious communities, but also to different individual religious views and those are usually strongly established within firm outlines. Discussions on faith therefor are not always and everywhere possible or desirable. People don’t come nearer to each other and it is better to respect that and find a common ground in earthly matters that are less far from every day’s experience.