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Is it possible to experience time passing?

Suppose you had to explain to someone, who did not already know, what it means to say that time passes. What might you say? Perhaps you would explain that different times are arranged in an ordered series with a direction: Monday precedes Tuesday, Tuesday precedes Wednesday, and so on. But if time passes and space does not, then this cannot be the whole story. After all, locations in space are also ordered: London is to the north of Paris, Paris is to the north of Marseille, and so on. And even if space had an intrinsic direction, this would not make it the case that space passed. A direction only requires that there be an asymmetry; but a mere asymmetry would not explain the notion of passing.

Instead, you might appeal to experience. We experience time passing throughout our lives, or so it is claimed. Different people will give different accounts of the details. Some will emphasise the fact that experienced change, such as motion, has a dynamic quality that is absent from any spatial analogue, such as a difference in the weather between London and Paris. Others will emphasise the feeling that we are located at a single moment, the present time, but we constantly “move” through time, away from the past and toward the future. Perhaps others will appeal to the role of memory. But whatever the details, it may seem clear that there is some aspect of the way we experience time that allows us to grasp what is meant by “the passage of time”, and that tells us that time is indeed passing. Nothing, you may say, could be more familiar.

Unfortunately, however, things are not as they seem. The first sign of trouble lies in the fact that, as many physicists have noted, the passage of time does not feature explicitly in descriptions of the world couched in the vocabulary of physics. This is not to assume, question-beggingly, that time, as it features in physics, does not pass. It is just to say that physics requires only that there be a time series, and says nothing about one time being present, or time passing. Questions about the passage of time belong to metaphysics, not physics. But although we can adjudicate between competing theories of physics through observation, we cannot normally do the same for metaphysics. Putative metaphysical features are of the wrong kind to be possible objects of experience.

Astronomical Clock Face by Judith. CC BY 2.0 via Wikimedia Commons.
Astronomical Clock Face by Judith. CC BY 2.0 via Wikimedia Commons.

There are many ways to see the problem. Here is one: in order for experience to tell us something about the world, our experiences must have an appropriate sensitivity to the way things are. Your visual experience tells you about the words that you are reading because your visual experiences are sensitive to what is written. Had the words been different, the configuration of your brain, and thus your experience, would have been different in a corresponding way. If, instead, your experiences would have been the same, regardless of what was written, then you would not really be seeing.

There is no way for experience to be sensitive to whether or not time passes. This would require that the state of one’s brain be sensitive to whether or not time passes; and this cannot be so. For if we compare two theories that agree on which sentences of physics are true, but disagree on whether time passes, then because the two theories agree about which physical events occur, they cannot differ in what they say about the configuration of anyone’s brain. So, whether or not time passed, your experiences would be exactly as they actually are.

Here is another way to see the problem: As you read this page, there is an element of your visual experience, E, that concerns the words that you are reading, and other elements that concern the edge of the page, the side of the computer monitor, and so on. There is no deep mystery about how the elements and their objects match up. There is, for example, a single causal chain that leads from the words to E, and no similar chain from the words to any other element of experience. But the supposed passage of time would affect the whole physical world in the same way. Consequently it is hard to see what could make it the case that any one aspect of your experience, rather than any other, concerned the passage of time.

If, as suggested above, we have no way to grasp what it means for time to pass except through experience, and if, as I have argued, no experience could really be an experience of time passing, then we cannot claim to properly understand what it would be for there to be a mind-independent passage of time. The claim that time really passes is therefore empty, and should be abandoned. Instead, although there is a time series, there is no single ‘now’, and no passage. This raises the question of why we experience time in the way that we do. Answering this question is an important, fascinating and neglected project for metaphysics and the philosophy of mind.

Featured image: Clock by geralt. Public domain via Pixabay.

Recent Comments

  1. Larry Sherrill

    The human mind in fact in not limited to this moment. To experience the altering of the current moment has different levels of experience. Time change and precognition, though that is misleading, might be cited as the example of John Kennedy death. The intense shock we all felt at that moment was the altering of the future.
    Because of choices he would not make either as president of elder statesman in the future. Say we never went to Vietnam. You might marry a different person, have alternate children. Work alternate jobs and die an alternate death.
    The brain, of the moment, is habituated to its current future and in fact the brain lives in those moment and even alters the future. As an example anytime you measure a force or particle in science you affect that force measurement. So when you read the future you are actually there affecting it. ( I have supposed flood that future with anger and that people of that future might be angry.
    Time is violable, not to say that it is a good thing, so you can read something about your future??? But say you will be a trained scientist, that technique, method, library of observation would feed into your past and give you an instinct and perhaps a tallent for that future. In this you are already a part of your future. Succeed…

  2. Tom Llama

    I have problems with the concept of “time passing.” Relativity shows that movement through space is relative, and so is movement through time. We have atomic clocks that have demonstrated that, as an astronaut orbits the Earth, his clock returns a given amount of time behind a matching clock on the surface of the planet. What gives us an “order” in apparent events is entropy – since all events lead from a more ordered state to a lesser one, we perceive time as a movement from one more-ordered state to a lesser one )for example, a dropped egg to a cracked one, and not the reverse). A mechanical clock winding down or the half-life of a uranium-based clock behaves similarly. We measure time as the “distance” between any two such events. It makes far more sense for us to be moving through spacetime, like a train rider observing passing scenery, than spacetime somehow moving past us.

  3. Simon Prosser

    Larry, Tom, many thanks for your comments. A few remarks about Tom’s comments: Given the debate about passage, perhaps ‘movement through time’ is a potentially misleading way to describe what relativity shows. It does indeed show that measured intervals of time can be different in different frames of reference, and physicists sometimes even say that ‘time slows down’ in moving or higher-gravitational frames. But this is a misleading way to put things in the present context, because it doesn’t directly concern the passage of time – it could all be true even if time did not pass (those, like me, who deny that time passes do not deny that there are intervals of time or that these are different in different frames of reference). However a related phenomenon – the relativity of simultaneity – does notoriously create a prima facie problem for the passage of time insofar as this is associated with the idea that there is a common ‘now’ throughout the universe.

    As for entropy, note that at most this provides a way of defining a direction of time. But direction is not passage. There could be a universal direction to time, or indeed space, without there being passage (e.g. an arrow has a direction, but it does not ‘pass’). The claim about entropy, although popular, is not completely uncontroversial, by the way – it’s only a statistical phenomenon, so there is in fact a low (but non-zero) probability of a cracked egg reforming into a broken one. It’s compatible with the claim that the laws of physics are time-reversal invariant (i.e. in principle, if not in practice, everything could occur in reverse order). Some people think a more direct way to define a direction of time would be in terms of the phenomenon of CP invariance failure – a fairly uncontroversial case of a non-statistical temporal asymmetry in a physical process. But, as I said, direction does not imply passage (though arguably the reverse implication holds – if time passes, presumably it passes in some direction. It’s an interesting question for the defender of passage how the direction of passage would relate to physical asymmetries such as those associated with entropy or CP invariance failure).

    I’m not sure that it makes any more sense to suppose that we move through time than to suppose that time moves past us – whichever way we look at it, the difficulties described above concerning experience would still arise. But I find it interesting that some people definitely prefer the view that says that we move through time, whereas others prefer the description that says that the future approaches and the past recedes.

  4. jaspreet singh Sidhu

    Can we define time as occurence of events such as movement of electrons or even photons. When no event is occuring (at all scales), it will imply that time is not passing. And when events are occuring, then time is passing, or our movie is going.

  5. Simon Prosser

    Dear Jaspreet, There has been much discussion of whether there can be time without change, going back at least to Aristotle. Probably the most influential paper in recent years has been Sydney Shoemaker’s 1969 paper “Time Without Change,” Journal of Philosophy, 66 (1969): 363–381. Shoemaker uses an ingenious imaginary scenario in which time regularly ‘freezes’ in different regions of the universe at different intervals to argue that in principle we could indeed have reason to think there was a period of time in which nothing changed (though we could not experience that period). But once again, notice that this is a different issue to the question about whether time passes. I deny that there is temporal passage, but I don’t deny that there is time and change. So even if it could be shown that change is essential for time, this wouldn’t tell us anything about whether time passes (in the sense of ‘passes’ described above).

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