I've read your position on the definition of Kufr. Simply put, you state that only those who knowingly reject Allah's message can be considered Kafirs. Since no human can know in an absolute sense whether or not such rejection is truly deliberate and made in full knowledge of it being the truth, we cannot brand anyone as being a Kafir.
This concept is then extrapolated to infer that non-muslims also have an equally good chance of gaining Allah's Pleasure in life to come.
While this concept seems in keeping with my own finite appreciation of the concept of justice, and I am totally certain that Allah would not punish anyone for unknowingly rejecting Islam, I'd like to know to what extent this definition of Kufr and Kafir prevailed in the "Golden Era" of Islam. It is safe to say that the Islamic scholars of that age, living chronologically closer to the Prophet's time and living in a less complicated world would also have come to this conclusion in their understanding of Islam.
Is this apparent from the religious literature that survives from that day? Can you cite a respected Islamic scholar from the generations immediately succeeding the prophet who agrees with this definition of Kufr and Kafir?
I ask because this definition of Kufr will probably not be accepted by the majority of Muslims today. If you could demonstrate that your understanding of what Kufr entails was also shared by the classical Islamic scholars it would go a long way into convincing people that rather then creating an innovative and political correct interpretation of this concept, you are in fact taking them back to an understanding that was distorted over the ages.
Before I answer your question, I would like for you to appreciate that we stress the point that people of other faiths cannot be declared Kaafir (i.e. disbeliever) in the sense that they have rejected the faith and are destined to go to hell. In fact there are other connotations of the word also. It can sometimes be used simply to initial rejections, which may sometimes be based on arguments.
Another fact worth considering is that the case under discussion is that of a people as an entity. No individual among such rival nations can be called Kaafir. The Almighty deals with individuals separately. We know that those who claimed that they wanted to learn about the faith were exempted from the punishment to be executed upon the polytheists of Arabia after the Messenger had performed Itmaam-e-Hujajh on them.
Now I come to your question. What makes a certain group Kaafir is their rejection of a Messenger of God after Itmaam Hujjah on that group. After the Prophet Abraham (pbuh), the Almighty appointed the Israelites the status of the bearers of truth before the world (shauhadaa al annaas). They were made symbols of divine justice on earth before other nations. Because of this very status they could call their opposing groups disbelievers. The same is the case with the Ishmaelites after the transfer of status to them. They enjoyed this status until after the collective identity came to an end almost after a thousand years of their history. In this period all their rivals would certainly be called the kaafirs in their collective capacity.
Therefore, during the golden era of Islam Muslim scholarship did not have any problem in this regard. They truly understood the status entrusted to them. However, after the removal of their identity the Muslim scholarship also could not withhold its previous tradition. Their activity shrank to merely copying the previously produced works. That is the basic reason of absence of any noteworthy work in this regard.
1, 'Itmam al-Hujjah' means the removal of all excuse or doubt in relation to accepting the revealed truth of God.
2, For explanation of the concept of Shahadah al annas by the two branches of the progeny of Abraham please refer to: http://www.understanding-islam.com/related/text.asp?type=question&qid=1873.