The Book
Chuck--
I'm enjoying our discussion, and trust you won't think I'm monopolizing your time with another response; I'll try to keep this one brief, but brevity is not one of my most apparent qualities.
It is important that our backwards time traveler assure that he not make "recognizable" changes. Of course, the only person who would recognize them is the time traveler himself--and even then (as my discussion of Back to the Future Part 1 suggests), the only version of the time traveler who will continue into the future is the one for whom the altered history is the actual history he himself remembers, so no one will know what the original history was unless as part of the trip the time traveler makes a point of reciting the original history even after it is no longer his own past. But I digress. What is more important is that we understand that our ability to recognize the change is distinct from whether the change took place. Consider this. When the time traveler reaches 1980, he continues to breathe the air and release chemicals into it--at the minimum limits, barring some special protective suit, he is consuming oxygen and releasing oxygen with carbon and hydrogen (fused as water). Each atom of hydrogen or carbon which he releases into the environment is stolen from the future and released in the past; each has a "temporal duplicate", another identical atom which is the same particle of matter from another point in the time stream. At least some of the oxygen which he releases in the past is also from the future, existing now in the past as a temporal duplicate of itself; even that which he uses and returns in the past is now linked to atoms from the future, at least temporarily, and so will have a different individual history. Our traveler will also take some of the oxygen from the past back to the future--we'll say 2000--creating a period of time from 1980 to 2000 during which there is an increased amount of total matter in the world, much of it in the form of increased hydrogen (linked as water) and carbon (linked as carbon dioxide) along with a net increase in the amount of oxygen (linked with those atoms), much of which is temporally duplicated, although some is merely from the present. There are also certain atoms which have been removed from the time stream entirely. Once the year 2000 arrives, these changes are reversed, as the excess carbon, hydrogen, and oxygen are taken out of the timeline and returned to the past. I, for one, cannot imagine that the exact same atoms would have found their way into the exact same people, given the changes in the available elements in 1980. I am forced to ask myself why the history of people should matter more to the time line in terms of pure physics than the history of atoms. The past has been eternally changed; it may never stabilize--but perhaps, since one atom is much the same as another and those which are not radioactive do not change with age (as far as we have determined), the details of which atoms are moved to the past or brought to the future are not so important as their total mass and nature. Again, the important point is that we understand that the past is changed by our very presence within it.
"Is the future of this ever so slightly changed timeline accessible?" I disagree with your statement that the altered timeline has not yet been established. Marty McFly's picture changes (although that is an unrealistic plot device) because he has changed the future; yet he is still in the past, so he can attempt to "unchange" it--something he cannot really do, although he can change it again to comport with his expected future. I've often said that trips into the future are no different than vacations in Boston--you leave for a while, and then you return. To your mind, no time has passed: you stepped into the time machine in 1980 and stepped out in 2000. But to the rest of the world, 20 years have been lived. There has been ample time for the "new" history to become established. There is no waiting for the past to change to reflect your changes--it has had the time to do so while you were gone. You imagine that because for you the time was skipped it must be so for everyone; but those changes are now history, and were lived by those people you left behind, and indeed by "Version-2" of you yourself. (History will not continue until the memories of the original history are gone, and even you remember only the altered history.) It is, in fact, the original timeline which is no longer accessible, barring some type of sliding technology.
Incidentally, even with sliding technology (and assuming that the multiple universe concept is correct), you cannot access the original timeline at any point after the moment you left, because that timeline has terminated. There would be timelines which contain an almost identical history, but that at the moment at which you remembered going back into the past, that did not happen. Whether you decided not to do so, or the machine failed to function, or there was a disaster which threw you out of the time stream entirely (or merely killed you), if another world exists with the history you remember, it emphatically does not contain an event in which you went into the past.
I don't know that I have ignored linear thinking. I still believe quite soundly that cause must precede effect. What I have done is separate my notion of "before" and "after" from the linear timeline. A Doctor Who impostor once said, "Having lived in the future, I can't very well die in the past." But this is patently false--as his hearers recognized. Why can I not have a linear timeline in which the years run 1996, 1997, 1998, 1999, 1996b, 1997b, 1998b, 1999b, 2000....Causes in 1999 could have effects in 1996b which they could not have in 1996, because 1996b comes after 1999 experientially--a valid linear timeline which differs from our calendar linear timeline.
Precognitive dreams are still uncertain things. James "The Amazing" Randi has very intelligently observed that every night all of us have hundreds of dreams, some forgotten forever, some remembered if we are reminded, some remembered vividly, and some recurring. Dreams appear to be fragments of subconscious bits of information which pass through our memory, and are filtered by our rules of perception of reality just enough to become comprehensible--that is, we may dream that we are flying, but we understand the concept because the images in our minds are best explained if we envision ourselves airborne. Given this vast amount of mental information, it is extremely unlikely that nothing we ever dreamed would ever resemble anything we encounter in the future--and the fact that our experience with such things often involves "remembering" more details as having been "part of the dream" when the event occurs suggests very strongly that it is our memory which comports to the event, and not the event matching our memory. However, given the fact that tachyons behave in a manner which under current scientific theory is best explained if we assume them to be moving backward in time (which is not the same thing as what is usually and inaccurately said of them), it is at least plausible that information from the future could reach the present by some means--although it is a far cry from subatomic particles to information in the mind!
The idea of this universe being a fragment of matter in some larger universe has an interesting appeal in fantasy; "Men In Black" ended with a tip of the hat to that notion, as the entire universe was a marble in a huge game of marbles. But if you ask yourself what evidence could be used to prove or disprove such a theory, what observable reality would be so if that were true which would not be so otherwise, what experiment could demonstrate that, you will quickly realize that it is not much use as scientific theory. At least in asking about the existence of God, we can adduce historical and legal evidence in favor of such a theory; in regard to your theory (which I understand you hold only as a musing and not as a belief), the only evidence I can see--that the universe is expanding, making itself larger without altering the total mass/energy within it--strongly suggests that if it is a fragment of some larger universe, that world is very different from anything we can imagine. (The only thing that comes to mind which might perceive itself as increasing in size while retaining the same mass/energy total would be the contents of an egg; even that would not be the same, but might in some way be analogous to the experience of the universe in some way--that is, the universe could be embryonic in your imagined larger universe, but the rules of that world would still have to be incomprensibly different.)
If you are correct that humans seek instant gratification through the path of least resistance (PLR, as my colleague E. R. Jones calls it), this is all the more reason to question why more people are not making more dubious choices. After all, it is through delayed gratification that we survive--going to work instead of spending the end of your money on an afternoon at the amusement park; sending candy and flowers to the girl at the other desk instead of accosting her in the elevator; buying chicken for dinner instead of filet mignon so that there will be dinner tomorrow also. The tendency toward instant gratification would have us reverse all of those choices, whatever the long-term consequences. And granted that some of us might recognize the hazards of living for today and dying tomorrow, it still seems unlikely that the world would have become so...so civilized, so decent as it has, if all worlds are possible and all choices are made. But for the multiverse theory, the fact that we are all 99% likely to do the right thing does not alter the fact that we are 1% likely to do the wrong thing, and therefore we create two worlds--one in which we do the right thing, and one in which we do the wrong thing. I say not: I say that whatever we actually did, we were 100% likely to do that, and would do that again were we to live through it again with no memories we did not have then, no changes in the circumstances of that event, no alterations in outside influences. There are an infinite number of "possible" results to any math problem--truly as many as there are numbers and fractions of numbers, what could be called a "large" or "dense" infinity--but there is usually only one actual result, and that actual result will occur every time. If you have the game FreeCell on your computer, you may have noticed that although the cards are dealt at random, you can select a game by number--because if you enter the same "seed number" into the random number generator, you will get the exact same sequence of "random" numbers, so that the cards will fall in the same pattern. If you take a person with specific genetic characteristics and specific experience who at a specific age is given a specific choice based on specific information, if nothing different goes into the decision, the choice will be the same every time, as long as it is the first time.
Thank you for the opportunity--indeed, the challenge--to explain my understanding of time against the background of excellent questions and hypotheses. As I mentioned to someone on ICQ, you force me to think--and that's important. I look forward to the next round.
--Mark
