You as an observer create the past. Every moment is built upon the moment that came before. So you create your past by simply observing this reality. This also means that any new divine knowledge brought into this reality from shamanic journeying changes all of reality. Not only does it change the present, but also the past and the future. This is because time is a flat disc not a straight line, and any new information brought into a closed system changes the whole ourboros of reality. This change is instantaneous and creates a divergent reality from the reality that came just a moment before. Once this divergent reality is created, the new divine knowledge will have always existed and will always exist in this new divergent reality. So we not only expand our minds with divine knowledge gleaned from other realities, we also change the very fabric of our reality with each shamanic journey.