My thoughts are that every soul to have ever lived or every iteration of the set of all souls can be characterized in a multidimensional character space. I consider each life to be either an iteration of a single soul or a unique soul, and the characteristics are many and each has polarity - a positive and a negative. So each soul or soul iteration can be described as a vector in character space. This vector has the ability to continuously change throughout the course of one's life. This vector is synonymous with the idea of a moral compass and I'll be referring to it as such from hereonout.
Now, should we be iterations of the same soul, then I believe that our moral compass transcends our lives and that when we die we begin our next life with the same moral compass we inherited from our previous life. Therefore, it is our goal to point our moral compasses towards the Light - towards righteousness. Enlightenment can only be achieved when one's moral compass is perfectly aligned. I believe that when this happens, we break free from the reincarnation cycle as at that point we have become one with God. In Christian mythology, purgatory is the state where sinners expiate their sins. This is akin to aligning our moral compass. Therefore, we are in purgatory and until we take to heart the five pillars, the five constants, the eightfold path, the ten commandments, and use these frameworks to align our moral compass, we will continue to exist in the reincarnation cycle and get glimpses of our past trauma.