Theory of compossibility

This explanation describes what Michael went through before blowing up the freighter better then any I have read. It also raises the question, “Is Michael alive/dead?”

NOTE: This is directly from! Not original content.

Theory of compossibility
David Lewis’ analysis of compossibility and the implications of changing the past is meant to account for the possibilities of time travel in a one-dimensional conception of time without creating logical paradoxes. Consider Lewis’ example of Tim. Tim hates his grandfather and would like nothing more than to kill him. The only problem for Tim is that his grandfather died years ago. Tim wants so badly to kill his grandfather himself that he constructs a time machine to travel back to 1955 when his grandfather was young and kill him then. Assuming that Tim can travel to a time when his grandfather is still alive, the question must then be raised; Can Tim kill his grandfather?

For Lewis, the answer lies within the context of the usage of the word “can”. Lewis explains that the word “can” must be viewed against the context of pertinent facts relating to the situation. Suppose that Tim has a rifle, years of rifle training, a straight shot on a clear day and no outside force to restrain Tim’s trigger finger. Can Tim shoot his grandfather? Considering these facts, it would appear that Tim can in fact kill his grandfather. In other words, all of the contextual facts are compossible with Tim killing his grandfather. However, when reflecting on the compossibility of a given situation, we must gather the most inclusive set of facts that we are able to.

Consider now the fact that Tim’s grandfather died in 1993 and not in 1955. This new fact about Tim’s situation reveals that him killing his grandfather is not compossible with the current set of facts. Tim cannot kill his grandfather because his grandfather died in 1993 and not when he was young. Thus, Lewis concludes, the statements “Tim doesn’t but can, because he has what it takes,” and, “Tim doesn’t, and can’t, because it is logically impossible to change the past,” are not contradictions, they are both true given the relevant set of facts. The usage of the word “can” is equivocal: he “can” and “can not” under different relevant facts. So what must happen to Tim as he takes aim? Lewis believes that his gun will jam, a bird will fly in the way, or Tim simply slips on a banana peel. Either way, there will be some logical force of the universe that will prevent Tim every time from killing his grandfather.

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28 yrs-old, attorney, father of 2

35 thoughts on “Theory of compossibility

  1. Yes! 100% behind this. I’m glad someone’s found a source for the way I’ve been looking at the limits of interaction with the past.

    It also brings to mind the coincidence/fate relationship. If you look at it from a perspective of faith, then it is fated that the guy won’t die until 1993. If you look at it from a science point of view, then a series of coincidences prevent him from dying at the hand of his grandson. One lucky guy (until 1993).

    Thanks Willis.

  2. Nope, you missed nothing BigD.
    It is broken down fairly easy, and I have heard people question the idea of what it actually means before.
    I think its a pretty good explanation on the subject for anyone that doesnt know.

  3. I understand it ok, i just thought that it was a more complicated version and was ging to ask why it had been over complicated thats all.

    If its not then thats ok 🙂 good post is deserved then lol

  4. The grandfather paradox is about the relationship between your grandfather and yourself in terms of conception. If you were to kill your grandfather before your mother/father were born, essentially you could not be there (not conceived) to kill him. Paradox.

    This is more to do with the timing of his death. It’s assumed that the killer’s parents here were already conceived in 1955, but that the grandfather can’t die in 1955 because he actually dies (written in history) in 1993.

  5. There are different ways to view this old paradox based on the many worlds or multiverse view of the universe or spacetime events.

    At decision points in the universe a new universe branches off representing the alternate decision taken. All decisions are therefore represented in the multiverse. all things are possible in one of the infinite universes making up the multiverse

    If I try to go back in time to kill my grandfather in 1955, i create a new possibility point in the universe. The original 1955 grandfather universe didnt have that possibility in it. A new universe spawns off in which my decision to assassinate my grandfather is a starting point. As a corollary there is a universe created in which I drop the gun and another in which I miss and so on..

    A yet other way of visualise spacetime and time travel is to think of it like cinematic film – as spacetime events sequential in nature. Loops cannot exist but time travel is still possible, new frames of film or new spacetime events are created not in replacement of the original film or events (because these events happened and were necessary to get the time traveller to this point), but tagged on the end of the spacetime sequence as additional spacetime events.

    If the writers of Lost are following the scientific script they will know about these fundamentals otherwise they end up in ‘back to the future’ territory. Whilst I agree with the course correctors idea, Faraday has said that time cannot be altered because its already happened.

    However if you knew that apocalypse was on the horizon, then creating a new spacetime sequence may be the way to create a better outcome for you and other humans capable of time travel. Maybe for humanity as a whole.

  6. Every decision i make results in a different outcome, no matter how insignificant that decision may seem at the time.

    Example: If i decide to walk to the shop to get a paper, along the way i meet an old friend and we decide to catch up on friday in the pub. That 1 decision of going for a paper has just changed my whole week let alone the choices i have to make before & after that.

    If however i didnt go and get the paper then i wouldnt have met my old friend and would do something different on friday night and thus different choices arise.

    To get to the point if a different timeline is created at every choice i make then the number of different timelines is infintesimle. Even if you were to just count the choices ive made this month the different scenarios that would arise are incaluable. For that reason i believe in 1 timeline only and thats my argument against timelines and timeloops. Like i said in a different post it would be like the tv show Sliders.

  7. Whatever happened, happened is the opposite of course correction. So if Daniel is correct then Ms. Hawking is incorrect. Highbrow, what is your stance on Ms. Hawking’s course correction?

  8. Course correction applies to Desmond and his ability to gain knowledge of possible future events. If he tries to change the future using this knowledge then course corection steps in

  9. Oops… user called and distracted me… sorry.

    anyway, course correction steps in and smacks Des on the nose with a newspaper. When Desmond tried to change something it’s important to note that it’s completely different than if our Pasties try to change something. Desmond does not time travel physically.

    I think Hawking and Faraday are both right. They’re just talking about two very different things.

    @bigdaveg: How does a decision you make now change your future? The choices you make in the present make your future. They don’t change it. How can you change something that hasn’t happened yet? If your decision has created a branch where you made decision A in one and decision B in the other then it’s important to remember that the only one that matters is the one you’re in! If you made decision A you’re on that timeline. The “you” that made decision B is on another branch and he’s a different person because we are defined by our decisions and our experiences. The decisions you-B makes in his future will have no affect on you whatsoever.

    Therefore, since alternate timelines and the things that happen in them cannot affect you then we can just ignore them. That is, assuming they exist. I don’t think they do.

  10. LOL highbrow that was exactly my point, there is only one time line.

    There are many roads to the town but you can only travel down 1 of these roads to reach the town, you cant split in half and go down 2 at the same time. I just dont think i explained myself clearly.

    The decision i make is the road i travel, what i was trying to say was if i travelled a different road the the journey to the town would be different thats all

  11. “For that reason i believe in 1 TIMELINE ONLY and thats my argument against timelines and timeloops. Like i said in a different post it would be like the tv show Sliders.”

  12. So we’re basically arguing the same point. Sweet.

    What I think is significant if you look at things they way we’re looking at them right now is that you can have one timeline with no branches (as you and I believe) or you can have multiple timelines either branching or being paralell (as some others believe), but it doesn’t matter. The other timelines are insignificant. So I think we can put the “multiple or single timelines” argument to rest.

  13. Lol same argument

    Yeah it makes me laugh as people have been arguing about this on every site ive been to, although never seen as much animosity towards believers and non-believers as hahaha

    I honestly thought they had found the right time line but then at the traffic lights red meant go and green meant stop. I was devastated hahaha

  14. I want to start off by saying I love the wording of both the wikipedia entry and Highbrows statement about alternate universes not mattering. I would also like to go ahead and say that I believe that (at least in terms of Lost) there is only one timeline we need to worry about and we can’t change what’s already happened.

    However, there is a flaw in your logic when it comes to time travel. This can be exemplified through what is going on in Lost right now. I’ll get to that in a second.

    Say we’re going through time on our time line in our universe with an infinite number of universes branching off at every decision we make. However, now we somehow find a way to leap backwards on our time line. Now even though we are still on our time line we can presumably make decisions that put us in one of these alternate universes. Now we are technically in two universes at once.

    When it comes to Lost, there were many decisions that led what was going on on the island when the losties crashed to happen, including Ben not dieing in 1977. Now that they have gone back in time they can send themselves into an alternate universe, one in which Ben Linus is dead, by shooting young Ben, an incident that never happened in the time line they were in. This wouldn’t effect the survivors of the Ajira plane crash and Ben would still be alive on the original time line.

    I’m not sure if I explained myself well enough, but I don’t think what I’m saying is going to apply in the upcoming episodes. When I see that Ben is shot in an unsurvivable way I think that John Locke survived an unsurvivable fall of 8 stories.


  15. the difference with the grandfather paradox is that it rules out both what is ‘physically possible,’ and what is ‘theoretically possible.’ certain actions are given a number based on different variables, and these variables determine if something is either physically possible, theoretically possible, both or neither.
    It reminds me of the situation with Michael before returning to the island. Physically he could kill himself, but it was theoretically impossible because he is the person who destroyed(s) the freighter.

  16. I think I see a light for the first time here.

    I can and have, written a theory of why change occures and how it works in THEORY.
    But…in real life, even if this was possible, there would be no way to prove it. Hmm, I dont like to admit when Im wrong so….highbrow, hows the weather in Michigan?

  17. Right, someone…special…that the rules you, I and even highbrow have discussed, dont apply to.
    What scares me, is going by by other theory…what if its Ben?

  18. Nice discussion here boys.

    Just one point to make amidst all this good, on track thinking…

    Highbrow: Please, don’t refer to the Losties/316ers/815ers/Freighter misfits/whoever as “Past-ies” without the hyphen as you did in an early comment …because without the hyphen it is “pasties” (as in ‘paste-eez’) and I completely was juvenile and cracking up for about 5 minutes…and then I had a hard time paying attention to all the smart things being said. I know, it’s my problem and all…but still. Wow…it was funny. 🙂

  19. I really shouldn’t read and comment late at night when I’m ridiculously tired.

    This really is a great discussion. I almost wish there was section that posts could go as reference points. I know that is somewhat the purpose of Lostpedia…but not really when it comes to theories and the foundations of certain theories.

  20. Kimberly, I thought the same thing first time I saw ‘pasties.’ Reminds me of a case I read in law school/Constitutional Law on obscenity. Justices said obscenity isn’t something we can define, per se; but you, “Know it when you see it.”
    Back on topic, I think this confirms time travellers cannot change the past. However, I believe Desmond(et al.?), through Faraday’s research and experiencing high levels of electro-magnetic forces, CAN change the past by sending information into the past and/or sending one’s consciousness into the past.

  21. Another example covered by this theory is The Titanic. Theoretically, a person could travel to the Titanic and rescue certain passengers onto a lifeboat before it sinks.

    If the person placed in the raft did not originally die when the Titanic sank, everything will continue and the survivor can go about his/her life. If the person originally died when it sank, that person would have a heart attack, stroke or something because they were supposed to die at that given time.

    As Compossibility states, One CAN save a person from the Titanic because it is physically possible to put someone on a raft. However, One CANNOT do this because it is logically impossible to time travel and change the past and because that person dies at that given time in history.

    This is significant for Michael, because if he did not originally die on the same day the freighter exploded, maybe he is still alive? Maybe this is why JIN is alive as well?

    This theory may require multiple timelines, loops (or maybe both?) but my line of thinking is that Michael could not die until the date/time the freighter exploded or after because he originally did not die until after that date. That would also explain why Jin was on the deck of the freighter when it exploded, yet he floated safely to the island, seemingly unharmed.

    As I remember, it was a huge explosion and Jin was standing only a few yards above the bomb. Yet he landed on a piece of wood and floated to the island without injury and without memory of what exactly happened.

    Let me know what you think. Does this make sense?

  22. It’s been raining off and on all day here A.E.S. I hope Karen has her umbrella…

    Kim, I think of that every time I type “pasties”. You can’t make me stop.

    As for multiple timelines… If at every point in time a new timeline is formed for each possible decision that can be made at that time then, guess what… the timeline where Ben dies and the DI never gets purged already exists! Nobody has to do anything to bring it about! So in that case, changing the past is kind of pointless…

  23. Highbrow…I don’t know if a “new timeline” would have to be created at every point in time. I will think about why. But come back and join in the discussions. Geez…what, do you have a life or something?

  24. Just to add to the “pasties” comment. I’m from London, and everytime I read it – I see the phonetic, “Pass-ties” like a cornish pasty – or multiple cornish pasties even. (Pastry filled with meat and veg) Took me a while to realise you meant “past-ies” lol – sorry *sheepishly realise I haven’t added to the discussion…my bad*

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