• jorndoe
    3.6k
    Whatever time may be, it seems to involve duration and simultaneity, neither of which are arbitrary ramblings, but would have to be accounted for by (or included in) any theory of time:

    • duration: it takes time to get to work in the morning
    • simultaneity: we get to work about the same time in the morning, as agreed prior

    People sure have come up with a few ideas about time over the years (pun intended):

    • Zeno: motion is illusory
    • Aristotle, Hume: no change implies no time (an empirical perspective)
    • Kant: time and space are a priori (pre)conditions for all experience
    • McTaggart: bah, smoke and mirrors, nothing but illusion and humbug
    • Robb: time is a causal dimension of the world
    • Shoemaker: time without change is conceivable (and logically consistent)
    • A scientific approach: time is a (measurable) quantity of any kind of change

    An aggregate of duration and simultaneity, an entropy gradient, an irreducible or basic aspect of the universe, that we wish to quantify with clocks, subject to relativity, …? Whether time is fundamental or not, duration and simultaneity will have to be taken into account.

    For context, let’s just briefly examine non-spatiotemporality (like abstracts perhaps):

    • Suppose x is defined as not spatial, “outside of space”. Well, then obviously x is nowhere to be found. And x cannot have any extent, volume, area, length, or the likes, not even zero-dimensional (like a mathematical singularity).
    • Suppose x is defined as atemporal, “outside of time”. Well, then there can be no time at which x exists. And there can be no duration involved, x cannot change, or be subject to causation, cannot interact, and would be rather inert.

    Causation is roughly uni-directional interaction, or uni-directional aspects thereof — what we find as related, temporally ordered events. Causes and effects are events, and events are subsets of changes — they occur (in context).

    Suppose we were to reduce time/temporality to something else, then how do we account for that something else? There’s an analogy to be found in the diallelus, regarding ontological reduction. Can there be answers that do not admit further questions, even in principle? Doesn’t really seem like it, in which case we just find ourselves on some indefinite path of inquiry. wikipedia, iep

    It may be possible to argue that “time does not pass” for a free photon, or that a photon does not age, in some sense, by moving at light speed. Indeed, photons are thought to not decay. They can still interact, however, which can be a drastic change in reference frame. Does this lend credence to Shoemaker’s odd thought experiment?

    There’s also a linguistic oddity related to time. Time versus existence: Did/does time exist or was/is existence temporal? Expressing temporality in tensed language can be challenging. The term “to exist” also has past tense — our language can express things existing tensed — did exist, do exist, may yet come to exist. What, then, about time itself? Something’s fishy. Well, at least some things exist for some duration only, like processes, like dawn to dusk. But time itself would perhaps have to be referenced, or characterized, tense-less. Either way, we shouldn’t let our linguistic practices bewitch us (cf Wittgenstein). We have (possibly confusing) double-temporal proposition like “it is true now, that it rained the other day”. Contemporary cosmology supposes that time is an aspect of the universe, among others. The past was, the present is, and a future may yet come to be. The past already “solidified”, the future has not, and the present divides them.

    235px-World_line.svg.png

    Presentism and the A-series may lead to, or express, a form of idealism (philosophical, not political), and seems kind of inadequate. Process philosophy has more going for it.

    On the other hand, eternalism and the B-theory seem to lack what we experience indexically, and so is incomplete in some sense. There’s no privileged “right now” included, at least not without adding it to the model. But once I’m gone, I could be characterized, in part, as a 4 dimensional “blob” (in lack of a better term), my connected spatiotemporal locales.

    The growing block universe has a kind of intuitive appeal, and is a move from the block universe towards accounting more closely for a privileged now, albeit subject to some critique (like much else). Does the growing block already presuppose time, and hence cannot be used for setting out a model or definition thereof? Maybe, maybe not.

    Relativity is apparently compatible with eternalism and the B-theory, which may be inherent in how such theories are formed. It’s intended that no particular “now” is all that’s modeled; the descriptive power is exactly the independence of a special “now”. Relativity is commonly said to describe a non-Euclidean geometry of 4 dimensional spacetime, and operates on something akin to a block universe, but that seems inherent in how no particular “location” (like the indexical “here-now”) has a special status.

    (An odd but seldom noticed consequence of McTaggart's characterization of the A series and the B series is that, on that characterization, the A series is identical to the B series. For the items that make up the B series (namely, moments of time) are the same items that make up the A series, and the order of the items in the B series is the same as the order of the items in the A series; but there is nothing more to a series than some specific items in a particular order.) — https://plato.stanford.edu/entries/time/#McTArg

    Sometimes there’s a (possibly subtle) misunderstanding of eternalism, or a block universe, in that the universe is said to be frozen, static, something like that. This is inaccurate, however, since change already is modeled along the temporal axis. On eternalism, or the block universe, there “is” still time (— by the way, notice the present tense “is” here — it’s misleading due to our language). Claiming that the past exists now is incoherent. Should a future come to pass, then that’s what the block model is supposed to have (thereby also separating ontology and epistemology). Time is one of the dimensions, and the (rest of the) universe is not static, since it changes along the temporal axis. The part that’s “incomplete” (in lack of a better word) is just that no particular “now” is privileged. Rather, the model includes any “now” on equal footing, if you will, and so does not privilege our current, indexical, experienced, present now (without the quotes). And that makes perfect sense for models like relativity, where we want descriptions that hold for any “now”.

    Time is the fire in which we burn. — Delmore Schwartz, Calmly We Walk Through This April’s Day (1938)
    They say time is the fire in which we burn. — Tolian Soran, Star Trek: Generations (1994)

    ________
    • Heraclitus (Wikipedia article), “panta rhei”, “no one ever steps in the same river twice”
    • Parmenides (Wikipedia article), timeless existence
    • Time (Wikipedia article)
    • Time (Internet Encyclopedia of Philosophy article)
    • Time (Stanford Encyclopedia of Philosophy article)
    • Temporal logic (Wikipedia article)
    • Arrow of time (Wikipedia article)
  • jorndoe
    3.6k
    The above is something I'd once typed in elsewhere, and seeing a few posts about time, I thought I'd post it here as well.
    Comments welcome.
  • andrewk
    2.1k
    Jorn, what is your opinion of Shoemaker's claim that time without change is possible?

    It seems to me that for there to be no change the universe would have to be completely empty - always and everywhere, so no quantum particles popping in and out of existence. If it contains even one photon or particle then there is change, since matter is energy is waves, and waves involve vibration, which is change.

    If time without change is only possible in an empty universe, what could it mean to say that time 'exists' in such a universe? It seems an empty notion, which is kind of appropriate.
  • Marchesk
    4.6k
    It seems to me that for there to be no change the universe would have to be completely empty - always and everywhere, so no quantum particles popping in and out of existence. If it contains even one photon or particle then there is change, since matter is energy is waves, and waves involve vibration, which is change.andrewk

    I thought it had more to do with entropy? Our universe starts out in an extremely low entropy state for some reason, and is headed toward maximum entropy a long time from now. Once it reaches the maximum, the system can't be said to be changing in any meaningful way. The laws of physics are time-reversal, so anything popping in and out or waving has no direction.

    That's my limited understanding of the directionality of time.
  • Alec
    45
    On eternalism, or the block universe, there “is” still time (— by the way, notice the present tense “is” here — it’s misleading due to our language).jorndoe

    What does the "is" mean then, if not that it exists in the present tense? Either something is, was, or will exist so in what other way is the block universe said to "exist"?

    Claiming that the past exists now is incoherent.jorndoe

    Yep, that is certainly logically impossible, but that may just be the wrong way to say it. What if we instead say that the "Big Bang exists now" or "Napoleon exists now"? Instead of saying that these events and objects exist "in the past" and that the past currently exists, we just cut out the middleman. IMO, there is no conceptual incoherency in saying that.
  • Metaphysician Undercover
    13.1k
    Jorn, what is your opinion of Shoemaker's claim that time without change is possible?andrewk

    I'll offer my opinion. Physical change without time is not logically possible, but time without physical change is.

    Imagine that we divide time into shorter and shorter durations. At some point we reach a duration of time which is as short as is possible due to the limitations of physical change. This is the shortest possible duration of time in which physical change can occur. However, we can still imagine a shorter period of time simply by dividing that shortest period of time, within our minds.

    But is this shorter than the shortest period of time (according to physical limitations) imaginary or real? Suppose that a physical change occurs which takes the shortest possible period of time according to the physical limitation. This time duration is t1 to t2, and during this time the change occurs. The change itself cannot be divided, it is the quickest possible change. So at t1 Y exists, and at t2 Z exists, and this is described as a quantum of change.

    Now, something necessarily exists as a medium between Y and Z, to account for the difference between them. We cannot say that there is a physical activity such as a motion, which is Y changing to Z, because this motion would be itself divisible into parts. The physical activity is already described as one moment there is Y and the next moment Z, and an intermediate motion is not possible. Therefore we can conclude that the only thing which happens between Y and Z is that time passes. Y and Z are different states with no motion or physical activity intermediary between them. Yet there must be something intermediary to account for the difference between Y and Z. This intermediary is time itself. Therefore it is not only possible that time passes without physical change, but it is a necessary conclusion.
  • Madman
    7
    Yet there must be something intermediary to account for the difference between Y and Z. This intermediary is time itself. Therefore it is not only possible that time passes without physical change, but it is a necessary conclusion.Metaphysician Undercover

    This might be true. But it might also be possible that the intermediary to account for the difference in time is the change from Y to Z so is this a valid argument?
  • Metaphysician Undercover
    13.1k
    But it might also be possible that the intermediary to account for the difference in time is the change from Y to Z so is this a valid argument?Madman

    If you are considering that possibility, then you have misunderstood the argument. I realized that this could be a problem, and tried to word it to avoid that problem. Think of it this way. Imagine that the change is a motion, an object moves from location Y to location Z. Because it has been stipulated that this is the shortest possible change, it is impossible that the object traverses a mid way point, say X, because this would imply that the object traverse YX then XZ, and the possibility of this this has been denied. There cannot be a describable intermediary between Y and Z without contradicted the premise that the change from Y to Z is the smallest possible.

    So what we have here is a unit of change, a quantum, which is indivisible. However, from one state to the next, from Y to Z, time passes. There is nothing which is changing while this time is passing, or else we'd be able to describe that shorter change, occurring between Y and Z, but the change from Y to Z has already been designated as the shortest.. There is position Y, then there is position Z, which are two distinct positions. There is no physical change between these two, only time.

    Try this. Let's say that when change occurs, object A changes to become object B. Something happens in between, and this is "the change". We could say that during the change, object A becomes C then becomes B. But then we have a change between A and C, as well as between C and B. To account for these changes, we could place D between A and C, and E between C and B. As you can see, in this way we would face infinite regress.

    So we can make the assumption that there is a smallest possible change, to put an end to the infinite regress. This is supported by the limitations of material existence. So if that smallest possible change is denoted as the change of A to B, then we cannot assume any describable material existence between A and B, and all we are left with between A and B, is time passing. And time is necessarily passing to account for the fact that at one moment A is the case, and the next moment, B is the case. But no material change has occurred until B is the case.
  • vesko
    19
    ok friends, what is not clear to me is Will time be available outside the senses of any living thing, or does it exists only in our mind? It is impossible of course to check this as we are living creatures.
  • vesko
    19
    Quantum weirdness: What we call 'reality' is just a state of mind
    A lifetime studying quantum mechanics has convinced Bernard d'Espagnat that the world we perceive is merely a shadow of the ultimate reality
  • Metaphysician Undercover
    13.1k
    A lifetime studying quantum mechanics has convinced Bernard d'Espagnat that the world we perceive is merely a shadow of the ultimate realityvesko

    Sounds like Plato. But Plato didn't need quantum mechanics to come to this conclusion, he just analyzed all the other sophistry going on.
  • andrewk
    2.1k
    from one state to the next, from Y to Z, time passes.
    This is not necessary. Time could be discrete, like the integers, or like popes.
  • Sam26
    2.7k
    Ya, it seems that time, at least to me, is logically impossible without change. Even to say that a universe would be empty without change is meaningless, because a universe implies change by definition.
  • ivans
    12
    Time is a dimension of the universe which we perceive as change. Motion is not illusory any more than taste - humans simply have a sense of time.
  • Sam26
    2.7k
    Yes, we do perceive it, but there would be no perceiving without it.
  • Sam26
    2.7k
    Even if we existed as pure minds without physicality there would have to be change in some sense. For example, moving from one thought to another (past thoughts, present thoughts, etc.).
    Change can exist as purely mental events without space it seems to me, that is, it's certainly logically possible.
  • Alec
    45
    Ya, it seems that time, at least to me, is logically impossible without change.Sam26

    I think it goes deeper than that. Our concept of time is basically derived from our understanding of change. The fact is, if we did not perceive change in the world then we wouldn't have come up with this notion of a flow of time. Similarly, I don't think we can make sense of space either in a world without any physical objects. So to try, like Shoemaker does, to separate time from change and isolate one from the other sounds wrongheaded.
  • Sam26
    2.7k
    I said just the opposite, namely, that change isn't isolated from time. Change is analytic to time.
  • Metaphysician Undercover
    13.1k
    This is not necessary. Time could be discrete, like the integers, or like popes.andrewk

    There is a problem with assuming a discrete time though. This is because we experience a continuous time, so we have nothing but arbitrary points in time according to our experience. If we want to understand a discrete time it requires that there are points of division within time itself. So the problem is to find something real which differentiates one quantum of time from another.

    So suppose we have our units of change, Y and Z, and each one indicates a quantum of time. Time passes within Y, and within Z, and no time passes between Y and Z. This is opposed to the scenario I described, in which Y and Z were particular states and time passes in between these different states. Now under your proposed scenario, physical change is occurring at Y and at Z, but there is a necessary division between Y and Z, which separates one quantum of time from another. How could this be possible, and what could it look like? If it is a point when no time passes, what could that mean? Y and Z would necessarily be contiguous, but what could separate them? We can't represent it as a stoppage in physical activity, because this would mean that time passes here with no activity. So all we have is physical activity at Y and at Z with an arbitrary boundary between them.

    The boundary between two discrete units of time would necessarily be arbitrary and therefore the discreteness of time would just be an arbitrary assumption. The problem is that we do not know of anything which could act as the boundary, or divisor, between one unit of time and another. If you posit a period of time which is designated non-time, to divide time into units, then what is that non-time other than time passing with no change occurring? Then we are back to the other position, of time passing with no change occurring. So once you start to talk about reality existing as quanta, it is necessary to assume time passing with no physical change occurring. And if quanta are real, then it is necessary to assume time passing without any physical change occurring, because this is a necessary condition for real quanta. The other way, discrete time, ends up with arbitrary divisions, and not real quanta.
  • andrewk
    2.1k
    we experience a continuous time
    Do we though? How do we know we don't experience time like a movie, at 24 frames per second (or perhaps, 24,000). I don't think I could tell the difference.
  • Alec
    45

    Is there a difference between saying that change cannot be isolated from time and time cannot be isolated from change? It seems they express the same thing, that we cannot have one without the other, no?
  • Metaphysician Undercover
    13.1k
    Do we though? How do we know we don't experience time like a movie, at 24 frames per second (or perhaps, 24,000). I don't think I could tell the difference.andrewk

    As I explained, when you analyze this proposition there is nothing to make the boundaries between one frame and the next. So any such experience of time would need to consist of still frames of spatial (material) existence. But that just brings us back to my original description, in which Y and Z are the still frames of material existence, and time passes between them.

    If Y and Z consist of active frames within which there is a quantum of time, then there is nothing to separate Y from Z. We can't posit a time with no time because this is contradictory. So Y and Z must be described as contiguous units of time, with a point of separation. But that point of separation is just posited by us, as an arbitrary point in time. It is not a real separation, because we can't posit a "non-time" to make a real separation. Then Y and Z just are two parts of a continuous time, arbitrarily divided. The quanta are not real. To produce a model with real quanta, and a real experience of existence as a movie, we need to consider material still frames with time passing in between each frame. This implies time passing without any material change, in this intermediary period..
  • Sam26
    2.7k
    What I'm saying is that the meaning of the concept of the predicate is included in the concept of the subject. For example, "All bachelors are unmarried," or "All bodies are extended in space," which are instances of the meaning of the predicate being a function of the meaning of the subject. You can't have one without the other.

    Although the physics of time includes the idea of space, that is, time is a dimension of space, I don't think space is a necessary feature of time. For example, we experience time or change in dreams, but there is no spacial component. One could also imagine a mind or minds existing quite apart from space, and yet we could still experience a change in thoughts or experiences within the mind.
  • Alec
    45
    What I'm saying is that the meaning of the concept of the predicate is included in the concept of the subject. For example, "All bachelors are unmarried," or "All bodies are extended in space," which are instances of the meaning of the predicate being a function of the meaning of the subject. You can't have one without the other.Sam26

    Yeah, that was how I read your "Change is analytic to time". That was what I'm saying essentially, but it seemed like you were inclined to disagree for some reason which is why I asked.
  • Sam26
    2.7k
    You said "...if we did not perceive change in the world then we wouldn't have come up with this notion of a flow of time." My only point would be that there would be no "perceiving" without change. Thus, even the concept of "perceive" is temporal. Not necessarily a disagreement, more of a point of interest.
  • Harry Hindu
    5.1k
    Whatever time may be, it seems to involve duration and simultaneity, neither of which are arbitrary ramblings, but would have to be accounted for by (or included in) any theory of time:

    duration: it takes time to get to work in the morning
    simultaneity: we get to work about the same time in the morning, as agreed prior
    jorndoe

    What about time simply being a measurement of change? That is what "duration" is - a measurement of change using other simultaneous change to compare it to. The time, or duration, it takes to get to work is the amount of change that happens on the face of a clock, simultaneously. The little hand moves from the 8 to the 9 (about 1 hour) while you are driving to work and sitting in traffic. You can't measure change, if the other change (the measuring stick) isn't happening simultaneously with the change you are measuring.
  • Sam26
    2.7k
    There is no doubt that we do measure change, but there is also a sense where we don't measure anything, and yet we experience change. For example, I might say, "Time is moving slowly," that is, my experience of time is affected by my mental perception of it. The same with duration, it could be just an experience without any way to measure anything. I might be waiting for you to show up at a particular place, so I'm experiencing duration without any specific measurement. That's not to say that it couldn't be measured, but measurement is not necessary for the experience of change. I might also know that there are changes occurring without having a precise way of measuring those changes.
  • Harry Hindu
    5.1k
    I never said you can't experience change without a measurement. You can experience change, but unless you measure it, then you can't say how much time has passed.

    To say, "Time moves slowly" is actually saying that there hasn't been much change happening. Time seems to move slowly when we experience less change, as opposed to more change. This is why it seems like a long time has passed when we experience a lot of change at once, and why it seems like almost no time has passed when we experience little change.

    Because our minds function at different levels at different times (when we are sleepy, drugged, aging, etc.) we can't use our minds as measuring sticks of other change. This is why we use consistent, repetitive change as measuring sticks, like the rotation of the Earth.
  • Sam26
    2.7k
    I didn't say, you said "...you can't experience change without measurement." I was simply adding to what you said.
  • Harry Hindu
    5.1k
    But you didn't add to what I said because you seem to imply that we can have experiences of time, when I said that we don't experience time. We experience change.
  • Sam26
    2.7k
    Experiencing change is experiencing time - that's what it means to experience time. That's why I said earlier that change is analytic to time - you can't separate the two.
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