# Past, Present, Future **URL:** \ **Category:** Factual Questions\ **Created:** [August 5, 2004, 3:43am UTC](https://boards.straightdope.com/t/past-present-future/258402 "2004-08-05T03:43:47Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [August 5, 2004, 12:38pm UTC](https://boards.straightdope.com/t/past-present-future/258402/21 "2004-08-05T12:38:07Z")
The present is equivalent to a plane without thickness which is in constant motion. Only our perceptual abilities distinguish it from any other construct on the time dimension. E.g., “Midnight, GMT, Dec. 31, 1999/Jan. 1. 2000” is a similar plane recognizable by all but not in motion. There was an instant when it was the present, but it is now 4.67 years in the past. The surface of any solid object or any line or plane is similarly an object that is “real” even though infinitesimally small in one dimension. The whole idea of limits and surfaces would demonstrate that a given entity can be “real” even though having effectively no dimensionality in one direction of measurement. How one conceptualizes reality is probably key to the question here – a future subject to being changed by human action is indeterminate from the perspective of the present; is it therefore not “real”? ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [August 5, 2004, 12:56pm UTC](https://boards.straightdope.com/t/past-present-future/258402/22 "2004-08-05T12:56:16Z")
Firstly, mathematical objects are not real world objects. at best, they can be used as models of what is in the real world. So when you talk about a line or a plane, that is an abstraction – you cannot find lines or planes in the real world, though you canm find objects (e.g., a straight piece of string or a flat piece of paper) that approximate them. So a mathematical construct with three space dimensions and one time dimension, like the one that Isaac Newton used, is a good idealised model of the real world, but it is not the real world. What’s more, as Einstein demonstrated, even though it’s a good model for many purposes, Newton’s is not the best model available. Einstein’s model takes into account such things as the speed of light, which makes the universe look different to different observers. (In Newton’s model, the universe would look the same to everyone, apart from their different positions to observe the universe). The present moment is an abstraction, which can be modelled by the moving plane described by Polycarp. However, since we can’t observe an instant of time without duration, it can only be an abstraction. And Einstein’s model tells us that for us here on Earth, the present moment includes observations of events that took place thousands of years ago on distant stars. For observers on a planet going round one of those stars, the present moment includes events that took place on our sun thousands of years ago. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [August 5, 2004, 12:59pm UTC](https://boards.straightdope.com/t/past-present-future/258402/23 "2004-08-05T12:59:52Z")
Do the past, present and future exist simultaneously? It’s probably too early for me to be coherent, but I’ll try… The Past has happened; it cannot be changed. The Present is happening. We can make decisions and act upon them. In the Future any actions we take now will have already been done; thus the Present is the Future’s Past. We can’t change the Future, because anything in the Future will have already been caused by something in the Present or Past. For example, I am supposed to go to work today. It is in my Future. But let’s say I say, “Aha! I’m going to change the Future! I’m _not_ going to go to work today!” Have I changed the Future? No. Because in the Future, I will have been doing exactly what I was going to do based on my decisions in My Present/the Future’s Past. Now let’s say there is an observer 150 light years away, who has a telescope that has “infinite magnification”. That is, it can see a dime sitting on the sidewalk. The observer would be watching the American migration to the West, the Gold Rush, etc. To him, 1854 would be the Present. To us, it’s the Past. It’s like a film, really. The Present is what we’re watching now. The Past has already gone through the shutter, and the Future is at the end of the reel. But it’s all on one piece of film. The Past, Present and Future all exist at the same time and are only able to be differentiated by the observer’s frame of reference. So is this valid? Or is the Past obliterated the instant it happens, and does the Future not exist at all untill it occurs and is obliterated? ---
**Author:** ![ccwaterback](https://avatars.discourse-cdn.com/v4/letter/c/df705f/32.png) [@ccwaterback](https://boards.straightdope.com/u/ccwaterback)\ **Post date:** [August 5, 2004, 1:00pm UTC](https://boards.straightdope.com/t/past-present-future/258402/24 "2004-08-05T13:00:48Z")
IMHO, ooops wrong forum, but anyway … Past, present and future is all relative to what you are observing and how you are quantifying your time. At work, the past is yesterday and before, the present is today, and the future is tomorrow and after. At a drag race, the past is more than 5 seconds ago, the present is a car making a lot of noise and accelerating very rapidly, the future is waiting behind the starting line. For an Astronomer the past is billions and billions of years ago (hehe), the present is our current solar system, and the future is a theory. See how easy that works? 😃 ---
**Author:** ![Mithgard](https://avatars.discourse-cdn.com/v4/letter/m/e9bcb4/32.png) [@Mithgard](https://boards.straightdope.com/u/Mithgard)\ **Post date:** [August 5, 2004, 6:12pm UTC](https://boards.straightdope.com/t/past-present-future/258402/25 "2004-08-05T18:12:56Z")
Thanks ladies and gents, the posts have been fwd to my buddy 😃 ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [August 5, 2004, 10:27pm UTC](https://boards.straightdope.com/t/past-present-future/258402/26 "2004-08-05T22:27:47Z")
> [@Alessan](#): > > Technically, there’s no such thing as a “line” in geometry To be strictly accurate, there _is_ such a thing as a line in geometry, as well as points and planes and such, which are related to each other as described by an apropriate collection of axioms. What you mean is that there is no physical object which exemplifies our naive concept of a line. ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [August 5, 2004, 10:30pm UTC](https://boards.straightdope.com/t/past-present-future/258402/27 "2004-08-05T22:30:02Z")
> [@alaricthegoth](#): > > Was it not that philospher/poet Steve Miller, who said, like Paul. > > Time keeps on slippin’ slippin slippin into the future…? As I said [before](http://boards.straightdope.com/sdmb/showthread.php?postid=5136961#poststop), that only holds if you’re made of antimatter. ---
**Author:** ![kniz](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@kniz](https://boards.straightdope.com/u/kniz)\ **Post date:** [August 6, 2004, 5:49am UTC](https://boards.straightdope.com/t/past-present-future/258402/28 "2004-08-06T05:49:42Z")
> [@Alessan](#): > > Is there an echo here? **No, that is the past repeating itself.** 🆒 ---
**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\ **Post date:** [August 6, 2004, 2:43pm UTC](https://boards.straightdope.com/t/past-present-future/258402/29 "2004-08-06T14:43:28Z")
> [@Mathochist](#): > > Past is where time keeps on slipping as it passes an observer in the present. This, of course, is not the case for anti-observers such as the Steve Miller Anti-Band, which is properly an anti-band. For them, time keeps on slipping into the future. Of course Stevie Miller wants to reverse the stream of time. Humans tend to fall downwards through the air, but if time slipped into the future, then we might fall upwards, which would mean that we could kinda’ fly, you know… like an eagle. ---
**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:** [August 6, 2004, 7:54pm UTC](https://boards.straightdope.com/t/past-present-future/258402/30 "2004-08-06T19:54:07Z")
> [@](#): > > Humans tend to fall downwards through the air, but if time slipped into the future, then we might fall upwards, which would mean that we could kinda’ fly, you know… like an eagle. Nope. Time-reversed objects would still fall downwards. Gravity causes an acceleration, not a velocity, and since acceleration has two factors of time in it, you’d get two reversals, leaving the acceleration in the same (downward) direction. ---
**Author:** ![ZebraShaSha](https://avatars.discourse-cdn.com/v4/letter/z/eada6e/32.png) [@ZebraShaSha](https://boards.straightdope.com/u/ZebraShaSha)\ **Post date:** [August 6, 2004, 8:05pm UTC](https://boards.straightdope.com/t/past-present-future/258402/31 "2004-08-06T20:05:23Z")
How about this: Since everything is a quantum object we can view the existence of them as such. So, using this, the past could be a measured value after the quantum wave collapse, the present could be the state where there are infinite possibilities for the quantum wave collapse, and the future could be undetermined measurements of the future. [Previous page](https://boards.straightdope.com/t/past-present-future/258402.md?page=1)