A couple "technical" questions:
Reading the transcripts and listening to the lectures, LRH is asks people to "postulate" and "mock up" certain things such as cars, universes, and people. Then he proposes actions on these. Isn't he telling his audience to simply IMAGINE these things and then do imaginary actions on them?
I mean, you can't really *create* an object like this. The best you can do is imagine that object, but that is simply a mental image. Is LRH suggesting that simply imaging things makes them real, based upon the flawed assumption that when the e-meter registers something it must have mass and therefore actually exist?
In other words:
Mock-up something -> register on e-meter -> mass encountered -> exists
Good question, xenuphobe. I imagine you've been listening to the Philadelphia Doctorate Course lectures. I'll post a few quotes from 8-8008, which was the textbook for the PDC:
From Scientology 8-8008 by L. Ron Hubbard who wrote:
Creativeness could be found to exceed existence itself; by observation and definition it is discoverable that thought does not necessarily have to be preceded by data, but can create data. Imagination can then create without reference to preexisting states, and is not necessarily dependent upon experience or data and does not necessarily combine these for its products. Imagination could be classified as the ability to create or forecast a future or to create, change or destroy a present or past. (p. 15)
Creative Processing,  especially where it divorces all thought from thought of the MEST universe and follows out along a line of the rehabilitation of one's own universe without attention to the MEST universe, is one level of processing which produces magnificent results and which is a standby in any case, no matter how difficult.
 Creative Processing: the exercise by which the preclear is actually creating the physical universe. It consists of having the preclear make, with his own creative energies, a mock-up. (p. 53)
Cleared Theta Clear: a thetan who is completely rehabilitated and can do everything a thetan should do, such as move MEST and control others from a distance, or create his own universe; a person who is able to create his own universe or, living in the MEST universe, is able to create illusions perceivable by others at will, to handle MEST universe objects without mechanical means and to have and feel no need of bodies or even the MEST universe to keep himself and his friends interested in existence. (p. 146)
Control of the illusion is the essence of commands. The preclear must be able to create, grow, conserve, decay and destroy; start, change and stop; be, do and have; differentiate, associate and identify; handle in space, with energy and in time, any object, actual or mythical, in all the eight dynamics, and with high preference given to anything which disobeys "natural laws" of the MEST universe. (p. 157)
Hubbard, L. R. (1989). Scientology 8-8008. Los Angeles, Calif: Bridge Publications.
Here's some more "theory" and applications for Creative Processing.
From PAB 10 ca. late September 1953 Change Processing by L. Ron Hubbard who wrote:
As soon as one starts Creative Processing to the end of convincing the preclear that he can change things in space, he begins to find quite ordinarily that the preclear will get visios of roads. The road, of course, is the one thing which constructively changes the preclear in space. There is, of course, a scarcity of roads, and one remedies this with Viewpoint Processing by having the preclear mock up a great many roads for himself, somebody else with roads for themselves, and others mocking up roads for others, until the scarcity of roads is remedied. The road is also aberrative because it threatens momentary impacts to those persons who have been in accidents. Automobile accidents are, then, excessively aberrative since they are a hold-motion and a fixation on something which is intended as a continuance of motion. One of the simplest ways to handle this latter situation is simply to run the engram of the accident or to mock up accidents until the preclear is surfeited with them (by this last, of course, I mean that one has the preclear mock up the accidents).
One can also repeat this by having the preclear mock up the thetan moving the body as above and having the body moving the thetan. This last process is very productive. One does it in brackets. One has the preclear mock up something which he calls the thetan and then has this move the body as in the case of the parents above. Then he has others being moved around by their thetans and thetans moving others around, and then others doing this for others.
L. RON HUBBARD
In that the auditor directs the preclear in Creative Processing what to mock up, destroy, etc., the commands themselves can't help but reveal something of the psychology of the auditor. In the demo sessions in PDC #2 and #3, Hubbard had his preclear "mock up" things that are more than eerily reminiscent of his secret occult world and his "friend and comrade-in-arms"Jack Parsons
, who, in June that year, was killed in an explosion of fulminate of mercury. Hubbard had his preclear mock up explosions, a little man (homunculus) jumping through the ceiling, destroying oneself with "oh, what do they call that stuff--bichloride of mercury?" snakes, and temples. For more details of Parsons' death and his occult homunculus experiments, see Sex and Rockets
by John Carter, especially Chapter 10.