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Buddha taught us that Anatta, non self, is a key concept of the Dhamma, one of the 3 marks of existence. Basically we have a mind, not a soul, that differentiates from other minds by the kamma-vipaka it will experience, not by any inherent or intrinsic quality
In Tibetan Buddhism, there is this common search for the Tulku, reincarnated Lamas, such as HH Dalai Lama, but if we are all the same thing and there is no self, What is the meaning and the benefit or finding an reincarnation of someone?
This is a curiosity, not doubting the process or questioning the reasons, I'm sure there are good ones. I don't mean to be disrespectful.