The block universe, (II)

The simplest version of the argument is:

Things simultaneous to the same thing are equally real.

For any events A and B at different times, an event can be found that they are both simultaneous to.

Therefore, any events A and B at different times are equally real.

As a lifetime lover of Parmenides and Plato, I rejoice in the argument. The Aristotelian-Newtonian attempt to place the standard or intelligible principle for change in the universe failed, and so we are left seeing the universe as a participation in other.

That said, the block universe cannot mean that all events are simultaneous in time. Past, present and future or even earlier and later cannot be simultaneous. This is why the major premise spoke of things simultaneous to the same thing as equally real, though not necessarily as simultaneous to each other. This raises the question of just how temporal divisions can be allowed as equally real but not existing at the same time.

The simplest answer is just to say that the real is broader than the temporal. Without a realm transcending the temporal all times cannot coexist except at the same time, which is a contradiction. In this realm, time is whole, though it exists in its transcendent mode, and the time we know here is necessarily a broken image of this transcendent totality. There is no space-time loaf of the universe somewhere, starting at the big bang, with everything after it worming around. Such a loaf is not only unobserved but contradictory.  Better to replace it with something unobserved but at least possible.



  1. Kristor said,

    April 3, 2014 at 7:27 pm

    Boethius smiles. Einstein, too. This argument is at the same time cosmological, ontological, *and empirical.* A trifecta.

  2. Kristor said,

    April 3, 2014 at 7:32 pm

    And this: by way of its reliance on the notion of simultaneity, one of your premises presupposes the reality of time. So you’ve demonstrated timelessness from time.

  3. Lydia said,

    April 3, 2014 at 7:59 pm

    This is apparently the Stump-Kretzmann view of ET simultaneity. Is that deliberate?

    • April 3, 2014 at 8:00 pm

      It’s the first I’ve heard of such a theory. I don’t read many Analytics.

      • Lydia said,

        April 3, 2014 at 8:28 pm

        I should admit that I perhaps jumped to a conclusion and assumed that God was coming in here somewhere. Stump and Kretzmann use the concept of eternal simultaneity to explain divine timelessness by saying that God is simultaneous to every event that occurs in time.

        By the way, is premise 2 really true? Surely it isn’t a consequence of Einstein. ?? I make no claim to be a physicist but was under the impression that the whole relativity of simultaneity issue arises only for events that are already fairly close to one another in time. That is to say, I don’t think that anything in Einstein indicates that there is some observer’s perspective from which the Battle of Waterloo is simultaneous with the Battle of Midway!

        I say all of this as a firm B theorist. I believe in the block universe, though I entirely agree with you that it doesn’t exist in some sort of super-time.

      • April 3, 2014 at 8:47 pm

        Paragraph 1: Okay, I think I get it. I don’t think that’s what I was trying to do. I was shooting for an argument from time to the trans-temporal, or some sort of eternity.

        Paragraph 2: I go into more detail in part 1, where I conclude to a distance between T, Y, and X that can be made arbitrarily large (we can make the train in the example as large as we want, have the onlookers use telescopes, etc.). Note though, the claim is that there is some single event that one observer would see as simultaneous with Waterloo and another would see as simultaneous with Midway.

  4. Lydia said,

    April 3, 2014 at 9:08 pm

    Hmmm, so the idea is that if we got the train large enough that would be true concerning some event T (as the third event) and Waterloo and Midway? I’m going to have to ponder that and do a little digging. I have a feeling the speed of light is going to come in here at some point, perhaps as a limiting factor.

    • April 3, 2014 at 10:22 pm

      Speed is a limiting factor but we also can avail ourselves of some pretty extraordinary distances.

      • Lydia said,

        April 4, 2014 at 8:16 am

        Right, I’m beginning to get the hang of this. (After convo. with my Resident Expert.) So there could be some extremely far-away event E that from our local time perspective we would say “occurred a hundred years ago.” Yet a frame of reference can be found from which E appears simultaneous with my writing this paragraph. Ex hypothesi, E appears from *my* frame of reference to be simultaneous with an event that occurred locally a hundred years ago. Hence, an event that occurred on earth a hundred years ago appears simultaneous with E, yet, from a different frame of reference, the present moment appears simultaneous with E.

        Am I getting correctly at what you are envisaging?

        What this probably has to mean is that simultaneity cannot be treated as transitive in this example.

        It certainly does place a strain on any A Theory of time (with an Absolute Now), because it appears that any A Theory must choose a preferred frame of reference in order to designate what is future and what is past. This is even true for “growing block” universes and, a fortiori, for presentism (the view that only the present is real, that the past and future both are unreal).

        But then, presentism has enormous problems already, including the fact that it is radically unclear what it means even before you bring in Special Relativity.

      • April 4, 2014 at 8:51 am

        I think you are getting the argument exactly right.

        I considered the transitivity question, and I even wanted to write about it, but I thought it took the post too far afield. Ultimately, I edited out a discussion of it because because I didn’t see myself directly implicated in a the problem of the transitivity of simultaneity. My claim was that if X and Y were simultaneous with T they were both as real as T, not simultaneous with each other. I don’t think that this is just a verbal dodge: “simultaneity” can bring in ideas of reference frames, measurement, an observer, etc. that “reality” need not; and I am in fact making no claim about how X and Y relate to each other.

        More importantly, I think my argument depends on the denial of the transitivity of simultaneity, or that it is a refutation of it. The first premise is “take any two events X and Y happening at different times”. If simultaneity were simultaneous, then the events at different times would be simultaneous, which is contrary to the hypothesis. I’m trying to conclude to things at different times being equally real, not happening at once.

  5. ewcaetano said,

    April 3, 2014 at 9:27 pm

    I do not write well in english, so I ask your forgiveness for any mistake I make here. However, let me comment an important point of spacetime physics you seem to be missing. According with Einstein’s special theory of relativity, a subluminal reference frame (one moving slower than light) in which two events E1 and E2 separated by a timelike spacetime interval are simultaneous simply cannot exist. If E1 occurs before E2 and E1 can be, in principle, causally connected to E2, then E1 occurs before E2 for all subluminal observers. Only if you also allow for observers moving faster than light (superluminal) you can say that any pair of events can be viewed as simultaneous by someone. However, no superluminal particles – or observers – have been detected yet (and I believe they never will be). In general relativity this result remains the same, except, perhaps, if you allow for some odd spacetime topology.

    • April 3, 2014 at 9:50 pm

      I do not see your argument. The point is that E1 and E2 can be made both simultaneous with some other event T, depending on who observes them. Therefore, E1 and E2 are both as real as T.

  6. ewcaetano said,

    April 3, 2014 at 9:48 pm

    The single event that one subluminal observer would see as simultaneous with Waterloo and another would see as simultaneous with Midway cannot be causally connected either to Waterloo or Midway in special relativity.

    • April 3, 2014 at 9:52 pm

      The argument does not need a causal connection. Only simultaneity. I completely agree that causally connected events, for Einstein, happen before in time.

      • April 3, 2014 at 10:17 pm

        Note: my argument does not require Einstein’s relativity, but it does use ideas he made famous. All it requires is a finite speed of light and moving observers (and no fixed frame of reference like a center, circumference, or absolute space). No causality. No spacetime. Arguments like this are pretty common – Brian Greene gives a version of one on YouTube somewhere.

      • ewcaetano said,

        April 3, 2014 at 10:20 pm

        The causality point is that event T cannot “touch” or “know” of X and Y. Simultaneity as we usually understand it becomes a sort of local property in special relativity. It loses meaning as we expand the spacetime region of interest. Your first premise: “Things simultaneous to the same thing are equally real” does not look very clear to me in this context. Two objects in my table are real as I see and can interact with them at this very moment, but the light coming from a distant star does not mean that the star exists right now. It could have died a long time ago.

      • April 3, 2014 at 10:37 pm

        It loses meaning as we expand the spacetime region of interest.

        You mean Relativity works only at small distances?

        Your second argument proves my point. If two things are not equally real (the event of seeing a star, the star existing) they cannot be simultaneous. Thus, if they are simultaneous, they must be both real.

        I do not see what you are disagreeing with. I have never said that a signal must be received from something that exists, and I obviously think that such a claim is false. One can see it is false from the time delay of an echo.

      • ewcaetano said,

        April 3, 2014 at 10:41 pm

        I mean that simultaneity loses its usual meaning when we try to span large spacetime volumes.

  7. ewcaetano said,

    April 3, 2014 at 10:37 pm

    Reading again your premises, I think I have found a problem. You say that “Things simultaneous to the same thing are equaly real” (P1) and “For any events A and B at different times, an event can be found that they are both simultaneous to” (P2). I think that P2 should be rewritten as “For any events A and B at different times, an event T can be found which is simultaneous to A for observer S and simultaneous to B for another observer S'”. Never T is simultaneous to A and B for the same observer. Therefore, no observer can say that A and B are simultaneous to T and no observer can say that A, B, and T are equaly real.

    • April 3, 2014 at 10:58 pm

      no observer can say that A and B are simultaneous to T and no observer can say that A, B, and T are equally real.

      Your argument proves too much. If this were fatal to the argument, it would also be fatal to the relativity of simultaneity, since this principle also can’t be detected by a single observer. For that matter, it would be fatal to the equivalence of inertial reference frames since, in principle, no observer can detect whether he is resting or moving (or accelerating or in a gravitational field).

      Again, I’ve never claimed that the conclusion I reach is something that could be observed by a single observer. In fact, if an observer could just see what I’m arguing for, he wouldn’t need the argument.

      I’m going to bed now. Take the last word if you want. Many thanks, I had lots of fun.

      • ewcaetano said,

        April 4, 2014 at 8:03 am

        I have not read your previous post on the subject, and your previous comments as well. Now I understand what you meant and, indeed, I entirely missed the point.

  8. Bob Kurland said,

    April 4, 2014 at 5:07 am

    EW Caetano is quite correct. If one is talking about the whole universe, then an inertial frame (a frame moving without acceleration–i.e. without gravitational fields) cannot be defined for the total space, so In General Relativity simultaneity cannot be defined except locally over a small region. See

    “A local definition of simultaneity is an assignment to each spacetime event of a spacelike hyperplane that, roughly speaking, determines the events that are locally simultaneous.” [E. Minguzzi. Simultaneity in special and general relativity.

    For special relativity there is controversy over whether the definition of simultaneity is absolute or conventional, i.e. assigned on the basis of physical assumptions, e.g. that the speed of light is constant going from A to B and B to A See

    Stanford Encyclopedia of Philosophy, “Conventionality of Simultaneity”,

    That being said, I don’t understand your proposition because I still don’t understand what you mean by “real”–do you mean capable of being measured, being experienced or ??? . I’m not trying to be contentious, just trying to learn.

    • April 4, 2014 at 8:02 am

      If one is talking about the whole universe, then an inertial frame (a frame moving without acceleration–i.e. without gravitational fields) cannot be defined for the total space, so In General Relativity simultaneity cannot be defined except locally over a small region

      “Small” in this sentence can only mean “less than the whole universe”. This is fine. Nothing in my argument commits me to arguing for a universe-sized simultaneity.

      And again, I’ve said this before but it still bears repeating: this argument, though it is based on concepts made famous by Relativity, is not itself a part of Relativity as a physical theory. The ideas I use pre-date Einstein, like the idea that there is a finite time for the transmission of signals, that there is no special, immobile place from which all motions have place and time (like Aristotle’s container universe, Newton’s absolute space, or cosmic aether) etc.. I think these are enough for a working sense of the relativity of simultaneity. How large a space a physicist can make such relativity work over is a problem in physics as such, within the peculiar confines of the theory and the strictures of its method, and does not affect the argument here. That said, physics itself makes constant use of idealizations that cannot be physically realized: test particles, black boxes, ideal gasses, spaces without gravitational fields, an infinitely wide or small earth, etc. The inability to be realized physically does not preclude something from showing us the truth of physicla things. Thought experiments work.

      Let me say a word about “real”.

      This whole argument is a question about time, and so “real” has to be relevant to the question of how things are real in time. Most sides agree that time has an earlier and later; and it also appears to have a past, present and future. My argument starts with a very reasonable guy who says “if something is real, it exists in the present”. The guy is thinking something like “past things have disappeared, future things don’t exist yet, so that leaves only the present for things to be real in”. Now let’s take a guy who believes this and say “very well, you think that real things are in the present, and what is not in the present is not real. Do you also believe that if we postulate something simultaneous with a future thing, that it is also not real? or if (leaving side illusions and things like that) we posit something as simultaneous with a present thing, that it too is real?” Then I think he’d say yes. If he does, the argument kicks in.

      • Lydia said,

        April 4, 2014 at 8:20 am

        I see that this is then intended as an argument against presentism.

        To my mind, an even more damning (and even simpler) argument against strict presentism is the question as to how long this alleged absolute now is. If the Absolute Now is what makes things real, it seems pretty important as to how long it is. William Lane Craig has a several-page discussion of this and concludes, astonishingly, that the length of the Absolute Now is (wait for it) relative to the universe of discourse! I have great respect for Craig, but this is a crazy position to hold *if* one is a presentist. It’s all very well for us B Theorists to be loosey-goosey about how long to call “now,” but if one’s whole theory is that the Absolute Now makes stuff Real, one had better have a darned good reason for calling a length of time “now.”

      • April 4, 2014 at 8:38 am

        It’s an argument against restricting the reality of time to the now, and in this sense is against presentism. But it also tries to go from the reality of the now to a proof of the reality to what is outside of it, no matter how long we make the now. It is, if you like, a sort of cosmological argument for eternity, where “eternity” is understood as containing time and making it possible, and as being a fullness from which the imperfect existence of time itself is possible. “The block universe” is a metaphor that can only be cashed out by a reality transcending the temporal.

  9. ewcaetano said,

    April 4, 2014 at 8:29 am

    One thing is simultaneous to another thing only in the point of view of a reference frame (a set of rules and synchronized clocks registering events). The observer in reference frame S is the one who concludes: A and T happen at the same time. It does not make sense in physics to say that events occur simultaneously (or not) without mentioning an experimental setup to carry on position and time measurements consistently. So the question to the reasonable guy who believes that “if something is real, it exists in the present”, should be: do you also believe that if we postulate that someone is observing now (registering in its own set of clocks and rules) in your reference frame a future event in your reference frame (an event that your own set of clocks and rules does not register as happening now, but, let us say, 1 hour after now), than this future event is also real?

  10. ewcaetano said,

    April 4, 2014 at 12:09 pm

    I understand your reasoning as follows: if the observer-event Y is real for observer-event X and event Z is real for observer-event Y, than event Z is real for observer-event X (notwithstanding the fact that Z can be either in the past or in the future of X). I would like to see how you articulate this thought with the reality of substantial change. Is there any sense in which I can say something ceases to exist (leaves reality), given that, for example, persons dead a long time ago are alive for someone who lives now?

  11. Lydia said,

    April 12, 2014 at 3:19 pm

    A bit of blatant self-promotion. I just put up a post contra presentism that brings up Einsteinian considerations among many others.

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