# Is Time an illusion? **URL:** \ **Category:** Factual Questions\ **Created:** [September 2, 2010, 2:21pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385 "2010-09-02T14:21:18Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [September 2, 2010, 6:04pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/21 "2010-09-02T18:04:27Z")
> [@Elendil\_s\_Heir](#): > > > [@x-ray\_vision](#): > > > > A couple earlier threads: > > > > [Is time REALLY an illusion? - Factual Questions - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=429970) > > [If time is an illusion - Great Debates - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=296492) > > Oh, those threads are so _yesterday_. šŸ˜‰ Who can say? šŸ˜ƒ ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [September 2, 2010, 6:29pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/22 "2010-09-02T18:29:31Z")
> [@Meatros](#): > > I would agree with you - I think that the ā€˜illusionā€™ theory actually explains time and relativity better then the A theory. Well, that would be quite a lucky ā€œhitā€ for me, as I wasnā€™t responding to anyone really. Just going on a philosophical rant. On a quick reading of McTaggartā€™s theoryā€¦I donā€™t get it. It smacks of logical sleight of hand, like the ontological proof of god, or all the various proofs of 1 = 2. But I havenā€™t quite got my head round it to say for sure. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [September 2, 2010, 6:33pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/23 "2010-09-02T18:33:37Z")
Itā€™s a singular illusion. ---
**Author:** ![SmartAlecCat](https://avatars.discourse-cdn.com/v4/letter/s/67e7ee/32.png) [@SmartAlecCat](https://boards.straightdope.com/u/SmartAlecCat)\ **Post date:** [September 2, 2010, 6:38pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/24 "2010-09-02T18:38:17Z")
> [@Diceman](#): > > ā€¦now Stephen Hawking thinks that the fact that gravity exists somehow proves that thereā€™s no God. Thatā€™s not what he said. It was the other way around. He said gravity made it possible for the universe to exist without a God to create it. There could still be a God. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [September 2, 2010, 6:55pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/25 "2010-09-02T18:55:20Z")
> [@BlankSlate](#): > > Everything _is_ happening simultaneously, we just process it by applying a time frame. If this is true, itā€™s also false, because if thereā€™s no time, then the term ā€˜simultaneousā€™ is meaningless. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [September 2, 2010, 7:02pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/26 "2010-09-02T19:02:59Z")
> [@Meatros](#): > > I think the argument would be that what we refer to as time is actually a dimension - sort of. The _flow_ of time is what is the illusion. > > If you think of all events, past, present, and future as existent, you could say event X happened here (point on the map) at this time. That would, in reality (on the b theory), refer to an actual place. > > [Hereā€™s](http://www.fairfaxunderground.com/forum/file.php?2,file=5219,filename=Time_5.png) a picture that might help. Wellā€¦ yeahā€¦ I guess I thought that was a given. We live in a 4-dimensional matrix with position defined by (x, y, z, t). I have heard the idea that the apparent flow of time is driven by entropy. Since thermodynamic processes are not reversible, it isnā€™t so simple to move back in time. If moving north required us to reverse entropy, weā€™d all be headed south. And I have also heard the idea that the speed of light isnā€™t so much a cap on speed in the three dimensions as it is an absolute measurement of total speed in all four dimensions. In other words, the sum of the velocities in all four dimensions always comes out to c. Thus, you have time dilation - for things traveling very close to c in the three ā€œtraditionalā€ dimensions, they have less velocity left over for traveling through time. I donā€™t know how strictly scientific those two ideas are, but I like them. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [September 2, 2010, 7:07pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/27 "2010-09-02T19:07:27Z")
**Meatros** , shall I give you $100 tomorrow, or a thousand years from now? I guess it doesnā€™t matter: time is an illusion! So, bewitched by the illusion, I think Iā€™ll give it to you a thousand years from now. Itā€™s all the same to you, right? ---
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [September 2, 2010, 7:10pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/28 "2010-09-02T19:10:25Z")
> [@dracoi](#): > > Wellā€¦ yeahā€¦ I guess I thought that was a given. We live in a 4-dimensional matrix with position defined by (x, y, z, t). I donā€™t think it is a given - at least not as I understand it. It seems to me that most people still think in terms of the ā€œAā€ theory. Most people will talk of ā€˜timeā€™ coming into existence, for instance, with the big bang. > [@dracoi](#): > > I have heard the idea that the apparent flow of time is driven by entropy. Since thermodynamic processes are not reversible, it isnā€™t so simple to move back in time. If moving north required us to reverse entropy, weā€™d all be headed south. Iā€™ve heard of this as well. > [@dracoi](#): > > And I have also heard the idea that the speed of light isnā€™t so much a cap on speed in the three dimensions as it is an absolute measurement of total speed in all four dimensions. In other words, the sum of the velocities in all four dimensions always comes out to c. Thus, you have time dilation - for things traveling very close to c in the three ā€œtraditionalā€ dimensions, they have less velocity left over for traveling through time. > > I donā€™t know how strictly scientific those two ideas are, but I like them. I havenā€™t heard that, but it seems to make sense. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 2, 2010, 7:11pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/29 "2010-09-02T19:11:32Z")
> [@](#): > > ā€¦now Stephen Hawking thinks that the fact that gravity exists somehow proves that thereā€™s no God. Cite on this? As for this ā€œA time and B timeā€ business, Iā€™d be willing to wager that all of the main philosophers involved were completely ignorant of any of Einsteinā€™s work. Anyone can sit in their armchair and come up with something to fill a philosophy book, but it ainā€™t worth squat unless itā€™s based on observations of the real world. ---
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [September 2, 2010, 7:15pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/30 "2010-09-02T19:15:50Z")
> [@Elendil\_s\_Heir](#): > > **Meatros** , shall I give you $100 tomorrow, or a thousand years from now? I guess it doesnā€™t matter: time is an illusion! So, bewitched by the illusion, I think Iā€™ll give it to you a thousand years from now. Itā€™s all the same to you, right? You are confusing our perception of the flow of time and itā€™s ontology; You are perceiving the flow of time as an actual thing, not simply a dimension (a characteristic of a thing). I would say that if I receive $100 from you tomorrow, that it is set in stone - the time and place of my receiving the $100 cannot change. Whereas you, presumably, would say that it remains to be seen whether I will get the $100 tomorrow. The difference between our two views is that hypothetically, I could step into a wormhole, check to see if _I_ did get the $100 and then report back to this thread today. You, on the other hand, could not - hypothetically speaking. Rather, I should say, it doesnā€™t seem clear at all how you could. ---
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [September 2, 2010, 7:17pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/31 "2010-09-02T19:17:54Z")
> [@Chronos](#): > > > [@](#): > > > > ā€¦now Stephen Hawking thinks that the fact that gravity exists somehow proves that thereā€™s no God. > > Cite on this? > > As for this ā€œA time and B timeā€ business, Iā€™d be willing to wager that all of the main philosophers involved were completely ignorant of any of Einsteinā€™s work. Anyone can sit in their armchair and come up with something to fill a philosophy book, but it ainā€™t worth squat unless itā€™s based on observations of the real world. Actually if youā€™ll check out the posts, this is not the case. Itā€™s primarily because of Einsteinā€™s work that the B theory has adherents. The B theory makes sense out of relativity and simultaneous presents, whereas the A does not. This is, in my view, the selling point of this view. Did you read this thread? \*It should be noted that we arenā€™t saying you donā€™t exist, Chronosā€¦ šŸ˜‰ ---
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [September 2, 2010, 7:22pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/32 "2010-09-02T19:22:37Z")
From the Carrier link above: > [@](#): > > Scientists can only make sense of this if time is a location, part of a four-dimensional structure, so where you are in time is definable only relative to where everything else is in time. Which means everything else must already be there. So there is no absolute location in time. There is no ā€œnowā€ and thus no ā€œthenā€ or ā€œlater,ā€ except relative to other things in time (or other parts of you in time, since on RT you are a kind of four-dimensional person-tube, and you only see a cross-sectional slice of you at any given moment in time). - > [@](#): > > According to RTā€™s definition of time, where you are in time is only definable relative to other things in time (including other temporal slices of you). This means a future can only exist in RT if there is already a series of future events relative to which we are in their past. If there is something in the future relative to which we are in its past, only then does it remain meaningful on RT to say those events exist at a location in the future. Because their location is only in the future relative to us. Relative to those events, our future is in their past. And that entails all future events already existā€“we just havenā€™t gotten there yet. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [September 2, 2010, 7:23pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/33 "2010-09-02T19:23:53Z")
> [@Meatros](#): > > > [@Elendil\_s\_Heir](#): > > > > **Meatros** , shall I give you $100 tomorrow, or a thousand years from now? I guess it doesnā€™t matter: time is an illusion! So, bewitched by the illusion, I think Iā€™ll give it to you a thousand years from now. Itā€™s all the same to you, right? > > You are confusing our perception of the flow of time and itā€™s ontology; You are perceiving the flow of time as an actual thing, not simply a dimension (a characteristic of a thing)ā€¦ Bosh and nonsense. Any reasonable person would like $100 tomorrow rather than have to wait so long (with the certainty that weā€™d both be dead by then), thereby acknowledging that time is not an illusion. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [September 2, 2010, 7:28pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/34 "2010-09-02T19:28:47Z")
> [@SmartAlecCat](#): > > He said gravity made it possible for the universe to exist without a God to create it. > > There could still be a God. Interesting, Iā€™ve never heard of this view of his. Could you elaborate/point me to some elaboration? (Not wanting to cry ā€˜citeā€™, as I donā€™t doubt your claim, I just want to know moreā€¦) Anyway, as to the OP, Carlo Rovelli has been putting forward an argument (or a series of arguments) that in the still hypothetical theory of quantum gravity, there probably wonā€™t be any fundamental notion of time. The reason for this is that 1) the notions of time in quantum field theory and general relativity are fundamentally incompatible ā€“ the former regards it essentially as an external parameter relative to which dynamical evolution is to be measured, while to the latter, it is an inextricable part of the dynamics of the theory itself --, an inconsistency which getting rid of time altogether would solve neatly, and 2), as you go ā€˜deeper down the rabbit holeā€™ of physical theories, time gradually loses most of the properties we intuitively ascribe to it ā€“ going from thermodynamics to mechanics, it loses its directionality; going to special relativity, it is no longer unique, but rather, there are as many ā€˜timesā€™ as there are Lorentz observers; in general relativity, time is no longer external, but a dynamical quantity of the theory; in quantum mechanics, there is no really ā€˜exact momentā€™, time being subject to an uncertainty relation with its conjugate quantity, energy; and so on. In this sense, time might actually be regarded as an illusion, or at least, as non-fundamental; rather, it emerges from a timeless underlying theory. ---
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [September 2, 2010, 7:34pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/35 "2010-09-02T19:34:10Z")
> [@Elendil\_s\_Heir](#): > > > [@Meatros](#): > > > > You are confusing our perception of the flow of time and itā€™s ontology; You are perceiving the flow of time as an actual thing, not simply a dimension (a characteristic of a thing)ā€¦ > > Bosh and nonsense. Any reasonable person would like $100 tomorrow rather than have to wait so long (with the certainty that weā€™d both be dead by then), thereby acknowledging that time is not an illusion. The perception of the flow of time is the illusion. Time _is_ a dimension. Your ā€˜questionā€™ doesnā€™t actually deal with the heart of the issue. It seems to be a red herring, to be honest. The issue is this: A theory: The past existed (but doesnā€™t any longer), the present exists, and the future has yet to exist (it doesnā€™t currently exist). B Theory: The past, present, and future all exist - they are just various ā€˜placesā€™. From the wiki: > [@](#): > > Eternalism addresses these various difficulties by considering all points in time to be equally valid frames of referenceā€”or equally ā€œrealā€, if one prefers. **It does not do away with the concept of past and future, but instead considers them directions rather than states of being** ; whether some point in time is in the future or past is entirely dependent on which frame of reference you are using as a basis for observing it. In short, what you seem to want to target is how we experience ā€˜timeā€™; ie, the sense of flow (from the wiki): > [@](#): > > Subjective sense of flow > > Whilst the idea that there is some objective sense in which time is flowing can be denied, the fact that conscious beings feel as though it is in some sense flowing cannot. However, if the flow of time didnā€™t have an objective existence, then it is argued conscious beings would simultaneously experience all moments in their lives. A response is that since the brain presumably perceives time through information processing of external stimuli, not by extrasensory perception, and obeys the laws of causality, it is hard to see how the flow of time, whether it exists or not, could make any subjective difference: all conscious beings are built to perceive time as a chain of events, whether or not it occurs as such. There are some other interesting objections on that wiki page. What you are aiming your sites at though, isnā€™t a valid objection. It doesnā€™t actually deal with the issue. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [September 2, 2010, 7:39pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/36 "2010-09-02T19:39:36Z")
> [@CalMeacham](#): > > > [@](#): > > > > Commas may be used anywhere in dialogue or exposition to indicate the tempo of speech. I may have to use that over in GD, in the future. > > But if time is an illusion, then youā€™ve already applied it. And are applying it now. > > I have the feeling this entry wandered over from another thread. **Chessic Sense** hasnā€™t posted in this one yet. At least, not yet in the imaginary time frame _Iā€™m_ using. Just demonstrating how the future never becomes the past. Just a story that is part of the past. ---
**Author:** ![Superfluous\_Parentheses](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Superfluous\_Parentheses](https://boards.straightdope.com/u/Superfluous_Parentheses)\ **Post date:** [September 2, 2010, 7:45pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/37 "2010-09-02T19:45:37Z")
> [@Half\_Man\_Half\_Wit](#): > > > [@SmartAlecCat](#): > > > > He said gravity made it possible for the universe to exist without a God to create it. > > > > There could still be a God. > > Interesting, Iā€™ve never heard of this view of his. Could you elaborate/point me to some elaboration? (Not wanting to cry ā€˜citeā€™, as I donā€™t doubt your claim, I just want to know moreā€¦) I think this came from todayā€™s piece in the guardian regarding Hawkingā€™s new book: [Stephen Hawking says universe not created by God | Stephen Hawking | The Guardian](http://www.guardian.co.uk/science/2010/sep/02/stephen-hawking-big-bang-creator) Whatever you think of the guy, he does know how to get people interested in his books šŸ™‚ ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [September 2, 2010, 8:01pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/38 "2010-09-02T20:01:21Z")
There is also the concept of Plank time. Literally that is the unit of time that it takes light to travel one Plank length and the math is such that any event shorter than that can be said (by some theoreticians) to not exist. So the present becomes the past in one Plank time. Terry Pratchett had fun with the idea that within that time unit the universe is literally destroyed and recreated in a never ending series of single static moments that we then perceive as travelling through with continuity. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [September 2, 2010, 8:03pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/39 "2010-09-02T20:03:16Z")
> [@Meatros](#): > > ā€¦The perception of the flow of time is the illusion. Time _is_ a dimensionā€¦ Ah, but thatā€™s not what you flatly stated earlier, providing the spark to get this thread underway. You said, ā€œTime is an illusion.ā€ Now you say it is a dimension. A dimension could not be an illusion, could it? I presume you still have no objection to being given your hundred bucks a thousand years from now. And only a fool would say that, here in what we call ā€œthe real world.ā€ ---
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [September 2, 2010, 8:10pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/40 "2010-09-02T20:10:53Z")
> [@Elendil\_s\_Heir](#): > > Ah, but thatā€™s not what you flatly stated earlier, providing the spark to get this thread underway. You said, ā€œTime is an illusion.ā€ Now you say it is a dimension. A dimension could not be an illusion, could it? Ah, but I clarified in that thread, several hours ago: "I should, perhaps, clarify - the passage of time, IMO, is an illusion. Time is a dimension. Iā€™ve continued this in the other thread. " As to a dimension being an illusion, Iā€™m not sure how that makes sense. A dimension is part of a description of something, not a thing in and of itself. Unless you are a Platonistā€¦ > [@Elendil\_s\_Heir](#): > > I presume you still have no objection to being given your hundred bucks a thousand years from now. And only a fool would say that, here in what we call ā€œthe real world.ā€ :rolleyes: Iā€™ve pointed out how this misses the point. Ironically, you seem to be living in the pastā€¦ I wonder if this proves my contention or yoursā€¦ šŸ˜› [Previous page](https://boards.straightdope.com/t/is-time-an-illusion/552385.md?page=1) [Next page](https://boards.straightdope.com/t/is-time-an-illusion/552385.md?page=3)