# Does time exist? **URL:** \ **Category:** Great Debates\ **Created:** [October 14, 2004, 3:08am UTC](https://boards.straightdope.com/t/does-time-exist/269146 "2004-10-14T03:08:19Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Blackacre](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@Blackacre](https://boards.straightdope.com/u/Blackacre)\ **Post date:** [October 14, 2004, 3:08am UTC](https://boards.straightdope.com/t/does-time-exist/269146/1 "2004-10-14T03:08:19Z")
Hi folks! I’m new here and apologize beforehand if this is a dull, repetetitive question, but does anyone know if the “idea” that time doesn’t actually exist is making any headway among academia, physicists, etc.? Or has it been effectively discredited? Any information would be appreciated! BA ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [October 14, 2004, 3:15am UTC](https://boards.straightdope.com/t/does-time-exist/269146/2 "2004-10-14T03:15:29Z")
I’ll answer this in a few minutes. ---
**Author:** ![Tripler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripler/32/21807_2.png) [@Tripler](https://boards.straightdope.com/u/Tripler)\ **Post date:** [October 14, 2004, 3:42am UTC](https://boards.straightdope.com/t/does-time-exist/269146/3 "2004-10-14T03:42:39Z")
I submit that our perception of time is based on physical motion: the rising and setting of the sun, the movement of stars, rotation of objects, etc. Thus being, said motion is dependent on _energy_, which takes time. An impulse of energy (defined as a specific amount of energy in an unmeasurable instant of time–which, through calculus equates to basically administering an infinite amount of energy in no time) would more or less destroy an object. So, seeing as how we’re not all completely smashed into smithereenies from infinite energy at nonexistent time already, I would imply that the energy to set things in motion is not instantaneous, but infitesmally _gradual_, in that a set amount of energy needs _time_ to act upon things, in order to set them in motion. Therefore, time is dependent on energy acting upon bodies, forcing them into motion without destroying them. Which eventually leads to prehistoric man beginning to measure time from sunup to sundown, and millenia later, atomic clocks. Tripler I’ve actually studied this through electrical equations for certain circuits. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 14, 2004, 4:19am UTC](https://boards.straightdope.com/t/does-time-exist/269146/4 "2004-10-14T04:19:05Z")
Not quite sure exactly what you’re getting at, but there is still a faction of science that says that, notwithstanding **Tripler’s** perspective, the _progression_ of time is an illusion, that in the fabric of the universe time is a fixed dimension like the physical dimensions. The idea is that there is something about the way people (and probably other living beings) experience the universe that makes us think that time is moving. But I’ve never heard _anyone_ suggest flatly that there’s no such thing as time. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [October 14, 2004, 4:22am UTC](https://boards.straightdope.com/t/does-time-exist/269146/5 "2004-10-14T04:22:28Z")
I think what you’re after is more of a philosophical question. We perceive time to be flowing in one direction only. Physics describes a world where time exists as a parameter, without interpretation. Our perception isn’t really something that physics will answer. Stephen Hawking speculated that maybe we perceive time the way we do because entropy goes in one direction, and our brains follow the entropy. Is this kind of what you were asking? ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [October 14, 2004, 4:23am UTC](https://boards.straightdope.com/t/does-time-exist/269146/6 "2004-10-14T04:23:39Z")
There are dozens, if not hundreds, of theories about time being put forward by reputable scientists. Some say that time do not exist; most explain time by one means or another. There is no “official” scientific position, but the consensus is certainly for time’s existence. Einsteinian space-time seems to require it, and nobody has convincingly refuted old Albert yet. For example see this wonderful article [How to build the Universe](http://www.nature.com/news/2004/041004/full/041004-17.html) on the Nature magazine website. The notion that time _doesn’t_ exist may or may not be scientific but it makes for equally cool articles in the science magazines. Take a look through the archives of New Scientist, Scientific American, or Discover magazines and you’ll find scientists wasting all sorts of time on the topic. ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [October 14, 2004, 5:46am UTC](https://boards.straightdope.com/t/does-time-exist/269146/7 "2004-10-14T05:46:29Z")
> [@Exapno Mapcase](#): > > There are dozens, if not hundreds, of theories about time being put forward by reputable scientists. Some say that time do not exist; most explain time by one means or another. There is no “official” scientific position, but the consensus is certainly for time’s existence. Einsteinian space-time seems to require it, and nobody has convincingly refuted old Albert yet. Not that there aren’t interesting ideas. There’s a group in Toronto at the Perimeter Institute (IIRC) that has constructed something like either a quantum computer or a Penrose spin-network (depending on who explains it to whom) that has “spacetime” as an epiphenomenon rather than a primal object. I, personally, am interested in another idea which derives spacetime as an epiphenomenon from a topos-theoretic point of view. ---
**Author:** ![picunurse](https://avatars.discourse-cdn.com/v4/letter/p/7bcc69/32.png) [@picunurse](https://boards.straightdope.com/u/picunurse)\ **Post date:** [October 14, 2004, 6:47am UTC](https://boards.straightdope.com/t/does-time-exist/269146/8 "2004-10-14T06:47:13Z")
Of course time exists. otherwise, everything would happen at once. Then what would we do? ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [October 14, 2004, 9:56am UTC](https://boards.straightdope.com/t/does-time-exist/269146/9 "2004-10-14T09:56:51Z")
> [@picunurse](#): > > Of course time exists. otherwise, everything would happen at once. Then what would we do? Metaphysically, we would be eternal. From an objective reference frame with respect to space-time, everything has simultaneously not yet begun, is ongoing, and is finished. ---
**Author:** ![davenportavenger](https://avatars.discourse-cdn.com/v4/letter/d/5f8ce5/32.png) [@davenportavenger](https://boards.straightdope.com/u/davenportavenger)\ **Post date:** [October 14, 2004, 10:12am UTC](https://boards.straightdope.com/t/does-time-exist/269146/10 "2004-10-14T10:12:30Z")
> [@CurtC](#): > > Stephen Hawking speculated that maybe we perceive time the way we do because entropy goes in one direction, and our brains follow the entropy. Along these lines, there was a great short story by Ted Chiang called “Story of Your Life” about an alien race that saw the entire expanse of time at once. The aliens didn’t understand things like cause and effect, since to them both the cause and the effect had always been. It’s a really good story and has been serialized in a few places; it’s worth searching out. But yes, I don’t think it’s outside the realm of the imagination that time is something that is experienced by living things only, and doesn’t exist objectively. The problem is, how can you prove that? ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [October 14, 2004, 10:36am UTC](https://boards.straightdope.com/t/does-time-exist/269146/11 "2004-10-14T10:36:20Z")
> [@continuity eror](#): > > But yes, I don’t think it’s outside the realm of the imagination that time is something that is experienced by living things only, and doesn’t exist objectively. The problem is, how can you prove that? You would prove the following statement false by reductio ad absurdum: [symbol]"[/symbol]p(Fp)[symbol]$[/symbol]q(Fq)(Fp[symbol]®[/symbol]Fq), where F is the weak tense operator, “It will at some time be the case that …”. [http://plato.stanford.edu/entries/logic-temporal/](http://plato.stanford.edu/entries/logic-temporal/) ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [October 14, 2004, 10:48am UTC](https://boards.straightdope.com/t/does-time-exist/269146/12 "2004-10-14T10:48:50Z")
I should have added that the statement above cannot be proved false because it is true. Therefore, time is objectively real (metaphysically necessary), and there was time before there was life. ---
**Author:** ![davenportavenger](https://avatars.discourse-cdn.com/v4/letter/d/5f8ce5/32.png) [@davenportavenger](https://boards.straightdope.com/u/davenportavenger)\ **Post date:** [October 14, 2004, 10:49am UTC](https://boards.straightdope.com/t/does-time-exist/269146/13 "2004-10-14T10:49:16Z")
But the problem with this is that human beings created temporal logic. Human beings thought up logic period. And there is no person who has experienced time as anything other than forward-flowing. So we’re pretty much locked into thinking a certain way. We can’t think outside the box enough to really imagine what the universe might be like if there was no objective time; it’s not biologically possible. Even if we could build a giant computer that could “prove” the existence of time (or more specifically, the fact that time moves forward objectively), that computer would have been built by people who think a certain way, so the computer cannot even be objective. And how could we even trust ourselves to interpret its data correctly? ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [October 14, 2004, 11:08am UTC](https://boards.straightdope.com/t/does-time-exist/269146/14 "2004-10-14T11:08:50Z")
True. Of course, you’re destroying the foundations of actualism. But I’m okay with that. 😉 Thing is, though, logic is an a priori analytic entity and therefore precedes even existence itself. Were that not the case, then time (and also space) could not be used in mathematical equations to discern properties of the universe. In other words, if time is tied to perception, then so is existence. A modus ponens is true, not because of anything that exists, but because of the essential nature of truth. It is epistemically possible that, were man to be wiped out, gravity would behave differently, subatomic particles would come to rest, and force would equal something besides mass times acceleration. But the very emergence of man was tied to all these things behaving before as they behave now. The universe did not emerge from a brain; rather, it’s the other way around. A metaphysical impossibility, on the other hand, is objectively impossible. If time did not exist, there would be no universe. You can do the modus tollens. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [October 14, 2004, 11:59am UTC](https://boards.straightdope.com/t/does-time-exist/269146/15 "2004-10-14T11:59:54Z")
> [@Blackacre](#): > > I’m new here and apologize beforehand if this is a dull, repetetitive question, but does anyone know if the “idea” that time doesn’t actually exist is making any headway among academia, physicists, etc.? Or has it been effectively discredited? Any information would be appreciated! BA As a physical entity, NO. As a useful concept, YES. St. Augustine suggested that maybe time is measured in the mind. It is not an event itself that is measured, but instead, the impression that it leaves on the mind. The mind expects the future… which becomes the present… which the mind attends… and then becomes the past… which the mind remembers [Does Time Really Exist?](http://web.ask.com/redir?bpg=http%3a%2f%2fweb.ask.com%2fweb%3fq%3ddoes%2btime%2bexist%26o%3d0%26page%3d1&q=does+time+exist&u=http%3a%2f%2ftm.wc.ask.com%2fr%3ft%3dan%26s%3da%26uid%3d02E5C49B2F4844614%26sid%3d11894045E0796E614%26qid%3d254CE6E4489ACF4AB5D4E7DC252454FD%26io%3d0%26sv%3dza5cb0d8e%26o%3d0%26ask%3ddoes%2btime%2bexist%26uip%3d442fe47b%26en%3dte%26eo%3d-100%26pt%3dDoes%2bTime%2bExist%253f%26ac%3d3%26qs%3d0%26pg%3d1%26ep%3d1%26te_par%3d102%26te_id%3d%26u%3dhttp%3a%2f%2fwww.angelfire.com%2ftx5%2fblackdraxon%2fnew_page_38.htm&s=a&bu=http%3a%2f%2fwww.angelfire.com%2ftx5%2fblackdraxon%2fnew_page_38.htm&qte=0&o=0.) ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [October 14, 2004, 2:40pm UTC](https://boards.straightdope.com/t/does-time-exist/269146/16 "2004-10-14T14:40:29Z")
> [@Liberal](#): > > You would prove the following statement false by reductio ad absurdum: [symbol]"[/symbol]p(Fp)?[symbol]$[/symbol]q(Fq)(Fp[symbol]®[/symbol]?Fq), where F is the weak tense operator, “It will at some time be the case that …”. > > [http://plato.stanford.edu/entries/logic-temporal/](http://plato.stanford.edu/entries/logic-temporal/) Problem: Temporological topoi generally have Heyting algebra semantics which violate the law of the excluded middle, thus invalidating reductios. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [October 14, 2004, 2:43pm UTC](https://boards.straightdope.com/t/does-time-exist/269146/17 "2004-10-14T14:43:08Z")
Time exists. We know this because that feeling you get after watching an infomercial lasting 30 minutes proves there are better ways to spend your time. Either that or time stood still. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [October 14, 2004, 2:56pm UTC](https://boards.straightdope.com/t/does-time-exist/269146/18 "2004-10-14T14:56:19Z")
> [@continuity eror](#): > > Along these lines, there was a great short story by Ted Chiang called “Story of Your Life” about an alien race that saw the entire expanse of time at once. The aliens didn’t understand things like cause and effect, since to them both the cause and the effect had always been. It’s a really good story and has been serialized in a few places; it’s worth searching out. This device is one of long-standing in sf stories. Probably the most famous use of it was the Tralfamadorians in Kurt Vonengut’s _Slaughterhouse Five_. From **Lib’s** cite: > [@](#): > > The logical language of Tense Logic contains, in addition to the usual truth-functional operators, four modal operators with intended meanings as follows: > > P “It has at some time been the case that …” > F “It will at some time be the case that …” > H “It has always been the case that …” > G “It will always be the case that …” This assumes a past and future. It cannot be used in a discussion of whether they exist. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 14, 2004, 3:11pm UTC](https://boards.straightdope.com/t/does-time-exist/269146/19 "2004-10-14T15:11:00Z")
> [@](#): > > From an objective reference frame with respect to space-time, everything has simultaneously not yet begun, is ongoing, and is finished. Does this mean that this thread has been moved to Great Debates and is still here in GQ simultaneously? Freaky 😉 ---
**Author:** ![John\_Kentzel-Griffin](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)\ **Post date:** [October 14, 2004, 3:39pm UTC](https://boards.straightdope.com/t/does-time-exist/269146/20 "2004-10-14T15:39:21Z")
It’s time this was moved to Great Debates. **DrMatrix** - GQ Moderator [Next page](https://boards.straightdope.com/t/does-time-exist/269146.md?page=2)