Which leads me to my next point, why is there so much disagreement among Sikhs when it comes to the interpretation of Guru Granth Sahib Ji? I do not believe Sikhi advocates reincarnation/heaven/hell because of the writings of Professor Baldev Singh, he is of the belief that it goes against Nanakian Philosophy. That being said, this is the only sangat I have ever been a part of that rejects the belief in reincarnation or some form of reward/punishment in the afterlife. Why is this? I was discussing this very issue with a few Sikhs last week and was branded a "heretic", someone even said I had been brainwashed and was not learning the true teachings of Sikhi. After reading Professor Baldev Singh's work, I guess I went through Guru Granth Sahib Ji with a bias and read every shabad in a way that would fit my preconceived notions of what the Gurus were trying to say. I always read it in a way so that reincarnation/heaven/hell applied to this life, and not the next. And it wasn't just a one time thing either, I have been told multiple times by Sikhs in the past that my beliefs about Sikhi were wrong, that they were too "Atheistic", that I was changing Sikhi and had strayed from the message of the Gurus.
So, pretty much, how do you guys know that your "version" of Sikhi is right, so far Professor Baldev Singh is the only "scholar" I have come across who would agree with the members of SPN about miracles/reincarnation/heaven/hell, everyone else would disagree, and the Sikhs I know in real life would disagree.
I come to my own conclusions after studying Gurbani. In my research work I would never take what another researcher says at face value. We meet, discuss findings, look at source documents, critically analyse findings, and assess how well this fits in with what is already known.
When I study Gurbani, I employ a similar approach. I analyse and try to understand in the context of other shabads I know. Sikhi is very pragamatic and grounded in the real world so it should make sense and not require blind faith. Most people (in my experience) who preach that you MUST believe in reincarnation have a superficial understanding of SGGS or are very influenced by Hindu teachings. This influence has come from the time after Guru Gobind Singh Ji was assassinated and the Sikhs at the time were hiding in the forests until the right time to fight. The Gurdwaras were taken over by Brahmins and our history has been infiltrated since. Brahmins are threatened by Sikhs as our philosophy challenges their supremacy.
Sikhi should be a personal journey without judgement of others. Work on understanding and exploring for yourself. Constantly learn, unlearn and relearn as Tejwant ji so well explains!
And perhaps it is a discussion for another day, but really quick without getting into too much detail, what is the general SPN consensus on the Dasam Granth? Some Sikh told me about how there is something in there about Guru Gobind Singh Ji being the reincarnation of Krishna, so do you think it has been changed? If you disregard it, what about Banis such as Japu Sahib, isn't that something Sikhs are supposed to read on a daily-basis? So do the practicing Sikhs of SPN who think Dasam Granth was changed also not recite Japu Sahib?
This is a topic that has been discussed extensively. There is a whole sub-forum on the topic!! Please take time to explore and investigate for yourself adn come to your own conclusions. Sikhi teaches us to think for ourselves! The search box at the top of the page is a brilliant resource for specific questions-one I use frequently! The second part of your question was discussed in a thread recently started by Ishna ji. See you in the DG section!!