1. The Nature of Universes
A universe is a self consistent package of rules and mockups. It will have space or the equivalent to separate the mockups. It will usually have time of some sort to handle the consecutiveness of events. It will have some kind of contents such as matter and energy. And there will be a set of rules concerning the operation of the whole affair.
MEST style universes similar to ours have been common for a long time, primarily because the penalty universes of the home universe era implanted a predisposition towards this kind of mockup. But many other things are possible and universes designed as traps or implants often go beyond the usual definitions so as to take advantage of the individual's ignorance and blind spots.
Universes are created by postulate, perpetuated by alterisness, and made real to others by agreement. The universes we are interested in running out at this level were postulated, alter- ised, and agreed upon. There is a great deal of relevant material in the Axioms, Phoenix Lectures, Philadelphia Doctorate Course, and other early Scientology materials. It will also greatly speed processing and understanding to first run spacation (PDC) with attention to mocking up simple little universes and observing the behavior of space and time.
As noted by LRH in one of his lectures, beings shift between universes by agreement.
Imagine a Universe with a red sofa and a red chair, and a second separate universe with a green sofa and green chair. Imagine someone agreeing with the red sofa and therefore being in the red universe. Now imagine him changing his mind and agreeing with a green sofa. He shifts to the green universe. Note that a consequence of agreeing with the green sofa is that he also winds up with the green chair. If he wants a green sofa and an orange chair, he either must alter-is the green universe (which could be hard if many other beings are agreeing on it) or he mocks up a new third universe with a copy of the green sofa along with an orange chair. Note that if he wanted to meet someone sitting on the green sofa, he would be stuck with the green chair since the other person would be there rather than in the new universe with the orange chair.
The thetan still has the ability to shift to a universe simply by agreeing with it. His current problem is not getting into a new universe but getting out of the old one. His agreements with this universe are very sticky and pinned down. He can easily get into contact with another universe by mocking up someone in it and agreeing with them but he only gets it in a vague sort of way because he wouldn't let go of his agreements here on Earth.
This was different in the early days. By this I mean the time period subsequent to separation from static but prior to having solidly agreed upon universes that one did not leave. The earlier scene (which is also the ideal scene toward which we are aiming) was one in which there were many agreed upon universes (and also many non-agreed individual universes) and they were being constantly mocked up and changed around by postulate. The individuals moved around between these by selective agreement.
Consider a being who is not dependent on food or clothes or any sort of mest since he can mock up his own if he wants anything. Under these circumstances, what sort of things would be valuable to him? It would be things like admiration, new and interesting creations, aesthetics, communication, etc. Basic things which are dependent upon interchange between beings. Here you have situations such as a being mocking up a universe and trying to make it aesthetic enough to be interesting to others. He does this so that others will agree upon it, admire it, and contribute to its reality. This leads to a sort of one-upmanship and trying to score "points" and eval and inval and art critics and all sorts of things. There is actually quite a high level of game condition and agreed upon penalties, etc. going on between beings who can create and destroy universes at will. It's really quite a lot of fun but it can look pretty rough to someone walking around in a meat body.
Besides the normal agreed upon universes that people get together in, you find another kind of agreed upon universe. This is a sort of "canned" or pre-defined universe that could be thought of as being like a movie is today. This sort of universe is postulated as a complete track. I.E., the time line as well as the space is mocked up when the universe is postulated. Imagine some pleasant movie being actually created as a full reality with all the perceptics etc. Now imagine that a "viewer" goes into agreement with the star actor and actually experiences the movie as if it was his own life. The track is frozen. He picks up the beginning of it and lives through it to the end and if it was really good, he might want to experience it again sometime. In this sort of movie, you generally have no freedom of choice within the universe. The track just runs you forward from beginning to end. It is a universe in its own right and is not located in space or time relative to any other universe. Its just there as itself and if you feel like agreeing with it and experiencing it, you just go for it. Of course, you do have the same choice that you have now if you run a tape in a VCR. You can stop the film or back it up or just turn it off. But you can't change it internally unless you want to copy the whole thing and do a remake of the story with variations.
There was actually quite a bit of competition involved in putting together these entertainment universes. A sort of Theta level academy awards so to speak. Sometimes heavy penalties such as a period of service or subjecting oneself to an unpleasant universe were gambled on bets as to whose mockup would be more popular.
There was also a flavor of "canned" universe that had some degree of choice in a manner similar to that of a video game or computer adventure game. I.E., there might be a number of canned scenes and you would go to different ones depending on key decisions that you would make, or there would be a set of canned targets that would come at you in random sequence and you would score points as you eliminated them. Here you have a series of mini- tracks all linked together with a postulated program. Anything you can make a computer or VCR do can be set up the same way in a series of conditional theta postulates. For example, you can make the postulate that if someone opens the door, then a green mouse will run out. This is really no more difficult than postulating that a green mouse will run out right now.
Note that under these circumstances, time travel becomes the equivalent of rewinding a VCR. This, of course is time travel relative to the track of a universe. Your own track is sequential regardless of whether you loop back through the track of a universe. You could play a bit with a VCR and recognize that you can "go back in time" by rewinding it a bit or "predict the future" based on having seen it before. If there is a calendar visible in the movie (the equivalent of the time tags on a picture or the actual time of a universe), you will see that the universe's time for a given scene is the same whenever you view it.
This does make dating difficult. What with many agreed upon universes, so that there is no single one with the "right" time, and with canned universes that have the same date each time they are visited, values such as x trillion years ago are not too useful. Time was not tied together between the different agreed upon universes and flowed at different rates so even if two people agreed to count things in "Earth" time, they might have vastly different dates for the same moment when they happened to be in the same universe together. Dating can be done relative to your own experience by seeing what things happened before and after each other for you.
Late in this sequence you will find the appearance of home universe. By this time the being was already slightly decayed. Instead of simply creating and destroying a multitude of individual actual universes at will, he wanted some agreement. So a large matrix of interconnected universes was set up and agreed upon. Each individual was assigned his own home universe in this matrix where he could mock up what he wanted. He invested so much time and effort and creativity into his home universe that he didn't want to let go of it. As a result, he could be trapped by it. This free theta period ends with the collapse of the home universe matrix into a single agreed upon universe.