# 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:** 1
**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, 2:21pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/1 "2010-09-02T14:21:18Z")
**Meatros** asserts that is, in post 35 here: [unravel the mystery - Factual Questions - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=576462) This might end up in GD, but let’s try it here to start. I will argue that it is not an illusion. It is a commonly-shared human frame of reference that has great and obvious social utility. Things happen, or don’t happen, with the passage of time. If time did not exist, we would have no sense of yesterday, today, or tomorrow, let alone five minutes ago or a century from now. Without time, everything would happen, or be happening, simultaneously, and that way lies madness. What say you? ---
**Author:** ![qpw3141](https://avatars.discourse-cdn.com/v4/letter/q/6bbea6/32.png) [@qpw3141](https://boards.straightdope.com/u/qpw3141)\ **Post date:** [September 2, 2010, 2:24pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/2 "2010-09-02T14:24:20Z")
Saying that time is an illusion is a perfect example of sophistry. “Time is an illusion, Lunchtime, doubly so” Douglas Adams: The Hitchhiker’s Guide to the Galaxy. ---
**Author:** ![BlankSlate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blankslate/32/80_2.png) [@BlankSlate](https://boards.straightdope.com/u/BlankSlate)\ **Post date:** [September 2, 2010, 2:26pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/3 "2010-09-02T14:26:29Z")
Everything _is_ happening simultaneously, we just process it by applying a time frame. ---
**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, 2:30pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/4 "2010-09-02T14:30:09Z")
> [@unravel the mystery](https://boards.straightdope.com/t/unravel-the-mystery/552056/29): > > When, people, use, commas, for, no, reason,. 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. ---
**Author:** ![qpw3141](https://avatars.discourse-cdn.com/v4/letter/q/6bbea6/32.png) [@qpw3141](https://boards.straightdope.com/u/qpw3141)\ **Post date:** [September 2, 2010, 2:45pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/5 "2010-09-02T14:45:09Z")
> [@BlankSlate](#): > > Everything _is_ happening simultaneously, we just process it by applying a time frame. So, presumably everywhere is the same place, we just process it by applying a space frame? ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [September 2, 2010, 3:18pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/6 "2010-09-02T15:18:29Z")
> [@](#): > > 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 you’ve already applied it. And are applying it now. I have the feeling this entry wandered over from another thread. **Chessic Sense** hasn’t posted in this one yet. At least, not yet in the imaginary time frame _I’m_ using. ---
**Author:** ![x-ray\_vision](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/x-ray_vision/32/351_2.png) [@x-ray\_vision](https://boards.straightdope.com/u/x-ray_vision)\ **Post date:** [September 2, 2010, 3:22pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/7 "2010-09-02T15:22:41Z")
A couple earlier threads: > **[Is time REALLY an illusion?](https://boards.straightdope.com/sdmb/showthread.php?t=429970)** > > Einstein said “…for us physicists believe the separation between past, present, and future is only an illusion, although a convincing one.” http://www.aip.org/history/einstein/essay-einsteins-time.htm And from another site: “Roughly speaking, the... > **[If time is an illusion](https://boards.straightdope.com/sdmb/showthread.php?t=296492)** > > My appologies if this thread is in the wrong forum, I’m not sure where to put it. OK, three questions for those who believe that time is an illusion, or, if you don’t, then I’d appreciate it if you do post, to post from the point of view of someone... ---
**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, 3:35pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/8 "2010-09-02T15:35:12Z")
> [@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_. 😉 ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [September 2, 2010, 3:45pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/9 "2010-09-02T15:45:17Z")
Time is an abstract idea that we humans use to plan and schedule our lives. The past is gone and can never be changed; the future hasn’t happened yet. All we have is now. Sure, we can predict what _should_ happen, and are able to do so with great accuracy. For example I’m going for lunch now, unless a large meteorite strikes me dead or something. I don’t know what the soup is though. I’ll let you know in the future if it was good or not. ---
**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, 4:06pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/10 "2010-09-02T16:06:49Z")
> [@](#): > > So, presumably everywhere is the same place, we just process it by applying a space frame? Yes, but it’s a very _big_ place. ---
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [September 2, 2010, 4:37pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/11 "2010-09-02T16:37:59Z")
When did theoretical physics turn into an exercise in nihilistic philosophy? First there was this “time is an illusion” business, now Stephen Hawking thinks that the fact that gravity exists somehow proves that there’s no God. Can someone please ask these guys to go out and do something useful? ---
**Author:** ![glowacks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/glowacks/32/5548_2.png) [@glowacks](https://boards.straightdope.com/u/glowacks)\ **Post date:** [September 2, 2010, 4:48pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/12 "2010-09-02T16:48:16Z")
Following the multi-world interpretation of quantum dynamics, one might say other times are special cases of other universes. If you already posit the existence of “parallel” universes, time becomes merely a part of how one understands how the laws of physics relate one moment of a universe to the next. The difference between one universe and another universe at a supposed instant (which might not be instantaneous to some observers due to relativistic effects) is comparable to the difference within a universe at one time to the next; what differs is how the laws of physics provide correlations between the two. That might just be complete nonsense, but at the very least I read it in some popular book on the nature of reality written by a physicist. At least he (at one time) thought it was the correct way to understand time. The idea that time “flows” was abhorrent to him, despite the intuitive truth of it. ---
**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, 5:25pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/13 "2010-09-02T17:25:39Z")
> [@Elendil\_s\_Heir](#): > > **Meatros** asserts that is, in post 35 here: [unravel the mystery - Factual Questions - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=576462) > > This might end up in GD, but let’s try it here to start. My bad, I completely missed this. > [@Elendil\_s\_Heir](#): > > I will argue that it is not an illusion. It is a commonly-shared human frame of reference that has great and obvious social utility. Things happen, or don’t happen, with the passage of time. If time did not exist, we would have no sense of yesterday, today, or tomorrow, let alone five minutes ago or a century from now. Without time, everything would happen, or be happening, simultaneously, and that way lies madness. > > What say you? It’s difficult to be clear on this, I find. It’s not that _time_ is an illusion in one sense - that is, it is a useful construct that we use throughout our lives. In another sense, the distinction between past, present, and future is - I think - an illusion. There are several theories on this, which can be lumped into two basic ideas. The A theory of time and the B theory. I support the B theory, put forward by [McTaggart](http://en.wikipedia.org/wiki/J._M._E._McTaggart). Here’s [his argument](http://plato.stanford.edu/entries/time/#McTArg): > [@](#): > > In a famous paper published in 1908, J.M.E. McTaggart argued that there is in fact no such thing as time, and that the appearance of a temporal order to the world is a mere appearance. Other philosophers before and since (including, especially, F.H. Bradley) have argued for the same conclusion. We will focus here only on McTaggart’s argument against the reality of time, which has been by far the most influential. > > McTaggart begins his argument by distinguishing two ways in which positions in time can be ordered. First, he says, positions in time can be ordered according to their possession of properties like being two days future, being one day future, being present, being one day past, etc. (These properties are often referred to now as “A properties.”) McTaggart calls the series of times ordered by these properties “the A series.” But he says that positions in time can also be ordered by two-place relations like two days earlier than, one day earlier than, simultaneous with, etc. (These relations are now often called “B relations.”) McTaggart calls the series of times ordered by these relations “the B series.” > > (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.) > > In any case, McTaggart argues that the B series alone does not constitute a proper time series. I.e., McTaggart says that the A series is essential to time. His reason for this is that change (he says) is essential to time, and the B series without the A series does not involve genuine change (since B series positions are forever “fixed,” whereas A series positions are constantly changing). > > McTaggart also argues that the A series is inherently contradictory. For (he says) the different A properties are incompatible with one another. (No time can be both future and past, for example.) Nevertheless, he insists, each time in the A series must possess all of the different A properties. (Since a time that is future will be present and past, and so on.) > > One response to this argument that McTaggart anticipates involves claiming that it’s not true of any time, t, that t is both future and past. Rather, the objection goes, we must say that t was future at some moment of past time and will be past at some moment of future time. But this objection fails, according to McTaggart, because the additional times that are invoked in order to explain t’s possession of the incompatible A properties must themselves possess all of the same A properties (as must any further times invoked on account of these additional times, and so on ad infinitum). Thus, according to McTaggart, we never resolve the original contradiction inherent in the A series, but, instead, merely generate an infinite regress of more and more contradictions. > > Since, according to McTaggart, the supposition that there is an A series leads to contradiction, and since (he says) there can be no time without an A series, McTaggart concludes that time itself, including both the A series and the B series, is unreal. > > Philosophers like McTaggart who claim that time is unreal are aware of the seemingly paradoxical nature of their claim. They generally take the line that all appearances suggesting that there is a temporal order to things are somehow illusory. Here’s another way to look at time ([eternalism](http://en.wikipedia.org/wiki/Block_time)) and the primary reason why I think the A theory is wrong: “Special relativity has shown that the concept of simultaneity is not universal: observers in different frames of reference can have different perceptions of whether a given pair of events happened at the same time or at different times, with there being no physical basis for preferring one frame’s judgments over another’s (though in a case where one event A happens in the past light cone of another event B, all frames will agree that A happened in the past of B). So, in special relativity there can be no physical basis for picking out a unique set of events that are all happening simultaneously in “the present”.” If there can be different simultaneous ‘presents’ then this suggests, to me, that the past, present, and future exist (and always do). It’s hard to see how, on the A theory, that it can account for simultaneous presents. If the past ‘disappears’ and the future ‘hasn’t happened’, then how is the grandfather paradox possible? How can the ‘present’ be relative to the observer? There are some objections (on the wiki), that primarily deal with how we perceive time. ---
**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, 5:29pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/14 "2010-09-02T17:29:09Z")
There’s quite a trend at the moment to declare things as illusions, or epiphenomenal. Usually this is in regards to phenomena that are unsolved and are somewhat confusing or paradoxical (with a small ‘p’). My view is that an illusion hypothesis has to bring something to the table. All “illusion” really means is that there is an explanation that better fits all observations than perhaps taking something at face value e.g. “I’m not really a vampire, it was just a dream”. If no explantion with better predictive power exists, then “illusion” is just handwaving away an unsolved phenomenon. ---
**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, 5:33pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/15 "2010-09-02T17:33:29Z")
I should note that while I subscribe to the B theory and I think I have somewhat of a grasp on it, I’m not an expert and it often confuses me. 😃 Here’s some more links: [Ontology of time](http://richardcarrier.blogspot.com/2007/02/ontology-of-time.html) - Richard Carrier For a really technical look at it (too technical for me), look at Quentin Smith’s work: [Here](http://www.qsmithwmu.com/philosophy_of_time.htm). ---
**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, 5:38pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/16 "2010-09-02T17:38:04Z")
Time is as much an illusion as height, width and depth. I suppose you could argue that all four dimensions are illusory. If so, go for it, but don’t single out time and pretend its different from the other three dimensions. ---
**Author:** ![Asympotically\_fat](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)\ **Post date:** [September 2, 2010, 5:45pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/17 "2010-09-02T17:45:25Z")
> [@Meatros](#): > > “Special relativity has shown that the concept of simultaneity is not universal: observers in different frames of reference can have different perceptions of whether a given pair of events happened at the same time or at different times, with there being no physical basis for preferring one frame’s judgments over another’s (though in a case where one event A happens in the past light cone of another event B, all frames will agree that A happened in the past of B). So, in special relativity there can be no physical basis for picking out a unique set of events that are all happening simultaneously in “the present”.” > > If there can be different simultaneous ‘presents’ then this suggests, to me, that the past, present, and future exist (and always do). It’s hard to see how, on the A theory, that it can account for simultaneous presents. > > If the past ‘disappears’ and the future ‘hasn’t happened’, then how is the grandfather paradox possible? How can the ‘present’ be relative to the observer? > > There are some objections (on the wiki), that primarily deal with how we perceive time. In general relativity it’s even worse! Defining even an observer-dependent concept of the present can be at best arbitary and at worst impossible. Infact if you allow a more general class of observer in special relativity you get many of the same problems with defining a ‘spatially-extended’ present as you do in general relativity. ---
**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, 5:47pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/18 "2010-09-02T17:47:57Z")
> [@Mijin](#): > > There’s quite a trend at the moment to declare things as illusions, or epiphenomenal. > > Usually this is in regards to phenomena that are unsolved and are somewhat confusing or paradoxical (with a small ‘p’). > > My view is that an illusion hypothesis has to bring something to the table. All “illusion” really means is that there is an explanation that better fits all observations than perhaps taking something at face value e.g. “I’m not really a vampire, it was just a dream”. > If no explantion with better predictive power exists, then “illusion” is just handwaving away an unsolved phenomenon. I would agree with you - I think that the ‘illusion’ theory actually explains time and relativity better then the A theory. As a point of reference, more philosopher accept the B theory over the A theory (according to [this site](http://commonsenseatheism.com/?p=5552)): 26.3% B-Theory of time 15.4% A-Theory of time 58.2% other Not sure what the ‘other’ is though… ---
**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, 5:56pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/19 "2010-09-02T17:56:48Z")
> [@These are my own pants](#): > > In general relativity it’s even worse! Defining even an observer-dependent concept of the present can be at best arbitary and at worst impossible. Infact if you allow a more general class of observer in special relativity you get many of the same problems with defining a ‘spatially-extended’ present as you do in general relativity. I think you are right - I think special relativity may just be easier to explain to people. ---
**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, 6:00pm UTC](https://boards.straightdope.com/t/is-time-an-illusion/552385/20 "2010-09-02T18:00:04Z")
> [@dracoi](#): > > Time is as much an illusion as height, width and depth. I suppose you could argue that all four dimensions are illusory. If so, go for it, but don’t single out time and pretend its different from the other three dimensions. 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. [Here’s](http://www.fairfaxunderground.com/forum/file.php?2,file=5219,filename=Time_5.png) a picture that might help. [Next page](https://boards.straightdope.com/t/is-time-an-illusion/552385.md?page=2)