Today's Seth points out that what we call the past, our memories of past events, are different for each individual, and that these memories change with time. This is not just a cosmetic or trivial change, but actual changes of past world lines to other probable variations of the same past event, or even the elimination of a past or future event through a present choice or decision.
Julian Barbour in his book The End of Time proposes a complete theory of physics without the assumption of time; rather, the universe is an infinite collection of possible moments with each moment arising with a consistent past and probable futures (in our linear time perception). Our Inner Self then chooses which moment to manifest, moment by moment, that is most consistent with our current attitudes, beliefs, thoughts, feelings, choices and decisions (our raw materials of manifestation) and our current desire, imagination and expectation (our tools of manifestation).
This is really cool because each moment really is brand new. When we make life-changing choices, they happen in a moment and we are presented a complete past and set of future probabilities that are consistent with it ... seamlessly. Thus, we never fix the past ... we literally create a new one!
"Because events do not exist in the concrete, done-and-finished versions about which you have been taught, then memory must also be a different story.
"You must remember the creativity and the open-ended nature of events, for even in one life a given memory is seldom a "true version" of a past event. The original happening is experienced from a different perspective on the part of each person involved, of course, so that the event's implications and basic meanings may differ according to the focus of each participant. That given event, in your terms happening for the first time, say, begins to "work upon" the participants. Each one brings to it his or her own background, temperament, and literally a thousand different colorations - so that the event, while shared by others, is still primarily original to each person.
"The moment it occurs, it begins to change as it is filtered through all of those other ingredients, and it is minutely altered furthermore by each succeeding event. The memory of an event, then, is shaped as much by the present as it is by the past. Association triggers memories, of course, and organizes memory events. It also helps color and form such events."
(The Individual and the Nature of Mass Events, Session 806)