What is time?

[InfiniteNow]

I do what I can. Your dichotomy is still false, and your tactics still trollish. :)

[ryan2006]

Time is a measurement of distance between two points. Since the world is eternal or infinite for whatever matter scientists can not measure it. What is out there we ask. We can only imagine:)

[ldsoftwaresteve]

I was just skimming through this thread and noticed "oh, we are being watched" :/

 

I thought I should comment that what looks like a LOT of math is mostly just me trying to learn the required mathematical concepts on the fly. My math knowledge is sorely lacking, and I need to figure quite a few things out in order to get a better grasp of Doctordick's epistemological analysis, i.e. to really start to see its implications.

 

I already have a pretty good idea about what implications there are, just I have to take them on faith when I cannot follow the math myself. But I have to say the implications seem very reasonable to me and I would not find it very surprising if the math checks out.

 

I talk too much sometimes, but I still wanted to say one more thing, not having that much to do with the epistemological analysis but with your debate about what we should mean by "real". Rainbows are said to appear "when sun shines onto droplets of moisture in earth's atmosphere".

 

Is rainbow to be considered "real" when there's no one observing it? (Don't worry, there's no one answer... depending on what one means by "real" :phones:

 

-Anssi

I am watching as a fan of both of you. There is a certain mentality that I like to relate to, a certain kind of observer that I find fascinating. Perhaps I find elements of me in both of you. Narcissistic much?

 

About the rainbow, no, unless there's someone perceiving it. The construct is created by the observer and by the positional relationship of the observer and the light passing through the water droplets. Good example by the way. When we project it into existence as an actual object, we might conclude that we can slide down it. Mentally, I suppose we can but not ontologically, if I understand the meaning of the word as you are using it. Could I have substituted the word, 'epistemologically' in place of 'Mentally' in the previous statement? (that's as mathematical as I want to get right now).

 

Anssi:

Note that I referred to the presentation as "epistemological analysis". It has everything to do with issues regarding "human knowledge", i.e. our methods of conceiving/perceiving reality. The only sense in which it implies something about ontological reality is that it explains how certain conceptions/perceptions - that are usually seen as part of ontological reality - are unavoidable consequences of certain symmetries forced upon our worldviews.

Our worldview being the 'road' laid down by our experiences. The concept of a rainbow being an unavoidable consequence of the way our perception works. And, in DD's terms, 'implies something about ontological reality' is a golden nugget.

 

ansii:

For example, if the math checks out, it proves unequivocally that it is valid to model reality relativistically, predictionwise. But at the same time it implies strongly that the source of the relativistic description is not relativity of simultaneity or relativistic spacetime construction in any ontological sense, since completely epistemological standpoint already makes that sort of description valid.

Assuming, of course, that the 700 pound gorilla is consistent. Still, just so I don't screw this up, please restate this another way. :phones:

 

Anyhow, the epistemological analysis itself does not include that much math and a competent mathematician could probably review the analysis throughout fairly quickly, and get to think about the implications. At least as long as that person really concretely and exactly understood what the math is describing.

concretely and exactly is the invisible rope across the sidewalk there.

 

Apparently this has proven to be difficult to communicate for various reasons. People clinging to naive realism (hey, having defined a thing does not make it ontologically real!) or refusing to believe that (initially) completely unknown data stream can be predicted meaningfully (and yet you all have learned enough english to understand this text... ...well kind of understand it :cheer:

I assume you mean the future, when you refer to completely unknown data stream.

 

Also note that people tend to base their query of reality on their perceptions, as if there is something ontologically given in the meanings that have been assigned to some otherwise unintelligible patterns. Let us not forget that any sort of perception of anything, no matter how simple, entails that the perceived thing/pattern/noumena had already been defined. I.e. some sort of identity had been assigned to some spatial/temporal pattern. When you make a definition, allowing you to tack identity on some pattern/noumena, it does not mean that suddenly ontological reality exists accordingly.

Agree. You say, 'rainbow' and I know what you mean.

 

The epistemological analysis does not suppose ontological existence of any specific defined thing, it only deals with necessary constraints that come to exist in any sort of self-coherent worldview (~set of "defined things").

Does the analysis still hold water if the worldview is weak? Or do you mean if it is self-coherent, it isn't weak?

 

This conversation is good on many levels. I think that mankind has made a habit of projecting into existence things which exist only in our minds. Hell, we've habituated the practice! We commit a fundamental mistake when we do that. And we do it all the time. And I suspect that somehow that mistake is the cause of a lot of pain and misery. The one big example I can think of besides 'time' is 'God'. God is the projection of our internal judge, or conscience into existence. And since we've never treated conscience as a science, we've never given it a rational home nor have we concerned ourselves with its design. It is the one big failing of science.

 

Thank God for philosophy.

 

;)

[freeztar]

This is indeed an interesting discussion Ansshi and Idsoftwaresteve, but please move the discussion over to the relevant thread to prevent this thread from drifting further off-topic. Thanks. :)

[AnssiH]

Well, I don't know about there being more than one answer. Certainly, if you understand how the rainbow comes to be, a specific rainbow only exists when the point from which it is observed is defined. Thus, if it is not being observed no "specific" rainbow exists. One could only say that the general concept really existed. :)

 

That's the answer I would see reasonable myself, but I was chiefly trying to probe what sort of meaning different people seem tack on the word "real"... hence the disclaimer "depening on what one means by real". Well let me open it up to everyone.

 

Someone might claim that "every possible rainbow" exists or "is real" all the time by the virtue of some specific interference patterns hitting the air molecules everywhere (presumably, and depending on chosen interpretation of QM). Or why not just by the virtue of those interference patterns existing (presumably) in space. (Let's not dwell on the subject of lense effects, it's not relevant in this context, just talking about the definition of "real")

 

Or with a different meaning tacked on the word "real", one would say the rainbow is not real even when you see it. There is no rainbow in the position where you conceive it to be, it only exists as a pattern in your eye. And not even in your eye, as - presumably - it is a pattern in the sensory data that had to be interpreted by the brain in a very specific way, so to give you the "illusionary" perception of some colourful object sitting in front of you somewhere inside your 3D conception of your environment.

 

These can both be completely valid arguments, depending on how one understands the word "real". It is painful to follow lengthy arguments about whether time is "real" when clearly each participant understands that word (and many other associated terms) completely differently. Come on guys, stop underestimating each others.

 

I like to throw that word "ontologically" in there somewhere to refer to the idea that some idea or definition that we hold would be actually somewhat (or exactly) how something exists in reality. That can be a confusing concept all by itself though, but the word usually helps more than hinders the communication. Also in these discussions one should understand the concept of noumena (wikipedia it), which refers to undefined reality. I.e. some unintelligible form that we cannot think about because our thoughts and perceptions are entirely composed of the defined entities and concepts that we formed all by ourselves, i.e. by defining entities we cracked reality into intelligible "things" and their associated intelligible behaviour by whatever criteria was useful for predictions (albeit we did this based on the behaviour of "noumena" of course)

 

btw, with these definition something as tangible as "matter" is not ontologically real at all, as there is also a specific (and very useful) definition for very specific behaviour of noumena that we have tacked with the word "matter". When you are holding a lump of clay in your hand, that's not a naive realistic clay in a naive realistic hand :) I mean, there are very specific processes going on making that clay and that hand stable entities, or more properly, making such definitions possible as "hand" and "clay" (and all the defined physical processes that go on to keep them together... or keep them from falling inside each others, or however you want to see the situation).

 

Another way to put it, just think about where you could claim to find the ontological border between an atom and space? Without very specific definitions, there is none, is there.

 

Anyhow, what about that simultaneity? That's where the discussion about the ontology of time gets more interesting (and also little bit more relevant to Doctordick's analysis, of people are interested about that side).

 

-Anssi

[AnssiH]

I am watching as a fan of both of you. There is a certain mentality that I like to relate to, a certain kind of observer that I find fascinating. Perhaps I find elements of me in both of you. Narcissistic much?

 

When I read your posts I thought you think a lot like I. You even get misunderstood a lot like I :)

 

I'll answer the rest of your post in the other thread... ...tomorrow. It's very late.

 

-Anssi

[Eclipse Now]

5:18 pm here in Sydney, what about your place?:)

[AnssiH]

I'll answer the rest of your post in the other thread... ...tomorrow. It's very late.

 

Since I promised;

http://hypography.com/forums/philosophy-science/11733-what-can-we-know-reality-28.html#post227884

 

-Anssi

[freeztar]

5:18 pm here in Sydney, what about your place?:hyper:

 

Hmmm...that must be some kind of time dilation or something cause your post header shows that you made the post at 3:24AM! :eek: :cheer:

[Jet2]

I may not be able to answer what time is but I do know one thing about it:

People say time is in our hand...that's so wrong! In fact, we are all in time's hand.

[Overdog]

...What is this attribute? Still no definitive definition of time. I say time is only a concept. Now you are saying that time is an attribute. Where is the science that says time is more than a concept?

 

I agree time is a concept, but to the question that it is an attribute of the universe, might I suggest causality as a possibility?

 

Causality - Wikipedia, the free encyclopedia

 

Is Causality "real"?.

 

Also, I wonder if there may be a problem with how we are talking about time, relativity suggests it doesn't make sense to discuss it as a thing seperate from space.

[Little Bang]

Does an electromagnetic wave exist in this universe? Yes, and it cannot if time is not a fundamental part of the universe. Everything in the universe is here because of time. You would have to be a fool or a simpleton to make any statement to the contrary.

[AnssiH]

Just a quick post before I head to sleep...

 

What I tried to point out earlier was that your arguments have quite a bit to do with however each one happens to define words like "time" or "motion" or "real".

 

Electromagnetic wave exists in so far that you want to define certain behaviour that way. I.e. identify some "pattern" as the doings of a "wave"; you suppose certain identity to a "wave" allowing you to see certain predictable behaviour on reality (~define reality in terms of waves). What is going on ontologically, a different matter altogether. (Just food for thought; Can you suppose there is any ontological validity to the idea of "identity" of anything at all?)

 

You know, when you say "time must be a fundamental part of the universe", you don't really communicate anything about the ontological nature of time. I have to assume that the essence of your argument was that "things" are in "motion" or "changing", and that it could not be so if there was no "time"(?)

 

I don't believe whoever questions the "reality of time" is questioning whether things are "changing" in their perception and whether that perception has something to do with actual reality. The question has to do with the ontological nature of that "change" that we perceive, and especially with the ontological validity of certain facets of some definition of "time".

 

For exampple, in our everyday definition we tend to look at "time" as something that just flows onwards at the "speed" we perceive it to. Which is of course undefendable idea if you also define perception as being caused by some defined "natural processes". According to that worldview, we could not even detect it if "time" were to jump forward or backward here and there, like a broken record player.

 

When all is said and done, we can define "time" (or "change" or "motion") in many different but selfcoherent ways. How you see "time" has to do with how it and many things associated with it are defined in your worldview.

 

It doesn't really matter that much how you happen to define it as long as it works as an explanation for reality, and whatever your everyday idea of it is, it's bound to have some ontologically undefendable facets to it anyway. Reality is not really all that much affected by however you want to see "time". You are pretty much just arguing over semantics.

 

Btw, considering the ontological side of what we call "space" will lead to exactly similar complications. First getting over all the different ways to define space, and then realizing all aspects of its definitions have something to do with how all sorts of associated components are defined in our worldviews.

 

Anyhow, as long as you are thinking about the reality behind your comprehension of "time", things get considerably more interesting if you think about how simultaneity has been defined in special relativity. In fact it would be plain wrong to ignore that issue with a thread like this.

 

I tried to bring that up earlier because the validity of relativity implies many rather different ontologies on time than would otherwise be seen reasonable at all. It would be healthy to see how these different ontologies are also self-coherent sets of definitions by themselves. And it would be interesting to hear how different people here see "relativity of simultaneity" existing in reality.

 

-Anssi

[ldsoftwaresteve]

Ansii:

(Just food for thought; Can you suppose there is any ontological validity to the idea of "identity" of anything at all?)

of course, I have to latch onto this one thing to respond to. Why did it speak lounder to me than the rest of it? Maybe because I'm still struggling with the idea of ontological.

 

Here's my definition of 'identity': a re-cognized pattern. Existence doesn't have cognition so there isn't anything behind the concept of identity except when you come at it from the point of view of a conscious entitiy. Existence doesn't have a point of view (well, it does, in the sense that it 'has' conscious entities).

 

On the other hand, there are long duration structures that we could assume have been around 'forever' unchanged through the continuum of nows. That hints at 'stable' as opposed to unstable and implies a fundamental building block.

 

Perhaps it would be safer to assume the fundamental building blocks have been around 'forever'. Perhaps not. If the identity of the fundamental building block 'kicked in' and then the universe, as we know it today started forming, maybe we could assume that since that moment, the structures we see and identify now were able to exist. i.e. no 'big bang'. just something that signalled everything to start working the way it does now. the 'Big Bang' should be renamed to 'Ta Dah!'.

 

And it's impossible to consider that without using the idea of time to do it. So, 'time' becomes part of a reference that we use to create identity. It's a way of tagging patterns that enables us to detect change.

 

Without memory, we couldn't tag the patterns. We probably wouldn't even be able to see them either. Short term, long term, very short term memory. Hmmm.

 

Our pattern recognition subsystem probably uses a different kind of memory during its processes. Or the memory it is using lasts long enough for the pattern to form. The pattern might be fed to another subsystem which attempts to integrate it into consciousness and hold on to it. That 'holding on to it' function includes revitalizing the pattern or 'moving' it to the kind of memory that is automatically revitalized. Different kinds of brain tissue.

 

If I take another step down this path, I'll be babbling like an even bigger idiot than I am now. Time to let it settle down. If I don't, I'll start regurgitating this 'food for thought'.

 

By searching for a pattern, we are condensing the experience of the filtering subsystem (direct perception) and it is probably the patterns that are being kept in longer term memory as opposed to all of the triggers responsible for forming the direct perception. I'm thinking zip file here.

[Overdog]

...It doesn't really matter that much how you happen to define it as long as it works as an explanation for reality, and whatever your everyday idea of it is, it's bound to have some ontologically undefendable facets to it anyway. Reality is not really all that much affected by however you want to see "time". You are pretty much just arguing over semantics.

 

Btw, considering the ontological side of what we call "space" will lead to exactly similar complications. First getting over all the different ways to define space, and then realizing all aspects of its definitions have something to do with how all sorts of associated components are defined in our worldviews.

 

Anyhow, as long as you are thinking about the reality behind your comprehension of "time", things get considerably more interesting if you think about how simultaneity has been defined in special relativity. In fact it would be plain wrong to ignore that issue with a thread like this.

 

I tried to bring that up earlier because the validity of relativity implies many rather different ontologies on time than would otherwise be seen reasonable at all. It would be healthy to see how these different ontologies are also self-coherent sets of definitions by themselves. And it would be interesting to hear how different people here see "relativity of simultaneity" existing in reality.

 

I have to agree with this...lead on.

[modest]

I tried to bring that up earlier because the validity of relativity implies many rather different ontologies on time than would otherwise be seen reasonable at all. It would be healthy to see how these different ontologies are also self-coherent sets of definitions by themselves.

 

I do believe this could be useful in better understanding time. Let's deal with a specific example and see if more than one understanding of time is possible to fully (and simply) describe the example.

 

Let's say Sally is in the center of a carousel (merry-go-round). Tommy is on the perimeter of the carousel and it is spinning at relativistic speeds. The ontology of the situation is as such:

 

Tommy repeats the same three dimensional path repetitively. Knowing his radius from the center of the carousel, it's possible to describe his location with an angle [imath]\theta[/imath]. But, tommy is not always at the same position. We must describe his change in position. In other words, he has a velocity:

[math]\omega = \frac{d \theta}{dT}[/math]

I believe it is necessary to write velocity in this way - with a dT. Some people want to say velocity can be "change in position" without a dT. But, that doesn't work, as is illustrated in this situation where Tommy is repeating the same position every revolution, is he repeating the same time? No. Tommy ages with T - not with position. If time were nothing more than change in position then we could mathematically define Tommy's age with nothing more than the angle. As the angle changed, so would his age. But he doesn't repeat the same age over and over with his position so we need this concept T (whatever it is).

 

To drive this point home we add Sally to the mix and an experimentally validated equation:

[math]\Delta T = \Delta T_0 \sqrt{1 - r^2 \omega^2/c^2}[/math]

 

comparing Sally's T which we call [imath]T_0[/imath] to Tommy's T. This tells us that Sally ages faster than Tommy. This is not an effect of observation. This is something that ontologically happens. Sally may age 10 years on this carousel while Tommy only ages one month.

 

My idea of time would be the concept that needs to be added to the above situation to fully describe what's happening. It's written as T and we call it time. However, you are claiming that there are multiple self-consistent ontologies of time that describe T here. I wonder if you can give a couple examples.

 

~modest

[AnssiH]

Here's my definition of 'identity': a re-cognized pattern. Existence doesn't have cognition so there isn't anything behind the concept of identity except when you come at it from the point of view of a conscious entitiy.

 

Or from the point of view of a model of reality.

"Identity" can be defined as an assumption of something being the "same" from one moment to the next (or "through time"). In an ordinary worldview something like a shadow or a rainbow is taken to not preserve its identity ontologically, but we assume some things do. What things, that depends on how did we model that "unknown data". Should serve you well to not take any identity on anything for granted.

 

On the other hand, there are long duration structures that we could assume have been around 'forever' unchanged through the continuum of nows. That hints at 'stable' as opposed to unstable and implies a fundamental building block.

 

We certainly tend to think there must be some fundamental building blocks out there, but even then we don't know if we have that tendency only because our comprehension of everything works that way, i.e. it is *our* feature to handle everything that way, not reality's.

 

Another point is that even if there are fundamental building blocks, it is always possible to create a plethora of valid "mental models" on top of them (to explain their behaviour). That means no experiment can make a separation between different models.

 

And it's impossible to consider that without using the idea of time to do it. So, 'time' becomes part of a reference that we use to create identity. It's a way of tagging patterns that enables us to detect change.

 

Well that sounds quite close to how it is in Doctordick's analysis. It's kind of a minimum definition, a reference to changes in our knowledge.

 

I'm cutting you out here because it seemed to me the rest was getting out of the topic a bit :)

 

I'll just comment that the main purpose of the whole "object definition" exercise has been to point out how our perception/conception of reality has quite a bit to do with our own subjective definitions rather than being just us probing objective reality directly. Whatever probing we do, we understand it based on a model we built out of our very own assumptions/definitions.

 

comparing Sally's T which we call [imath]T_0[/imath] to Tommy's T. This tells us that Sally ages faster than Tommy. This is not an effect of observation. This is something that ontologically happens. Sally may age 10 years on this carousel while Tommy only ages one month.

 

My idea of time would be the concept that needs to be added to the above situation to fully describe what's happening. It's written as T and we call it time. However, you are claiming that there are multiple self-consistent ontologies of time that describe T here. I wonder if you can give a couple examples.

 

Yes, though note that I've been using the word "ontologically" differently than you do. I use it differently in the next sentence as well; The underlying "ontological" reality behind "time dilation" can be seen in many different ways, though all different views can agree it is predictionwise quite valid to describe the situation as "Tommy ages more slowly".

 

E.g. are Sally and Tommy passing through "time dimension" of "relativistic spacetime" in real ontological sense, or is spacetime just mental construction and the actual ontology is perhaps closer to, say, all natural processes in Tommy's situation are moving more slowly than in Sally's (rather like clock slowing down under stress)

 

...or is the root of relativistic time description found from our methods of defining entities in unknown data. To investigate that route, you might want to take a look at that epistemological analysis.

 

I was bringing up relativity of simultaneity instead of time dilation directly because that offers a fairly simple route to considering what ontological implications relativity makes on time and associated components;

 

I have to agree with this...lead on.

 

In a pre-relativistic view we'd be quite inclined to believe that the reality around us is in some definite "now" state even when we are not yet observing that state.

 

In a relativistic view we'd be inclined to believe it doesn't. Because the notion of simultaneity (~now moment) is defined as relative to your direction of motion. In a naive sense you could imagine that clocks in alpha centauri move backwards when you are accelerating away hard enough (they'd do so beyond your sight of course).

 

For anyone who is not familiar with the notion of relativistic simultaneity, here's a thought experiment pasted & edited from my old post;

 

We are on earth, and there is a spaceship near Alpha Centauri, approaching us at steady speed. Assuming the light is approaching us at speed C, we can figure out what is the "real" moment when the spaceship is just passing Alpha Centauri. On earth, we put up a signal beacon at that moment.

 

SR says the moment "we put up the beacon" and the moment "the spaceship passes Alpha Centauri" are not really simultaneous in any inertial frame but in ours. I.e. when the spaceship receives a signal from our beacon, it can figure out when did the beacon go up, and assuming the speed of light to be C in its own inertial frame, it will conclude that the beacon went up much much earlier than when it was passing Alpha Centauri.

 

This means that when the spaceship had not yet even passed Alpha Centauri in your frame, in its own frame you had already put up the beacon long time ago; your future had already happened I.e. your future actions have "already happened" from the point of view of many inertial frames.

 

It also means that if the spaceship now accelerates ("brakes") to the same direction of motion where you are, it will come to share the simultaneity with you. For example, if in its original frame you had put up the beacon three weeks before it reached Alpha Centauri, then when it brakes, the clocks and everything on earth "rewind" back to the state where they were three weeks ago; to the moment when you were just putting up the beacon.

 

Of course the above doesn't really make sense as is, it's a consequence of certain way of understanding the "now" (which we got from certain way of modeling the timewise evolution of things). But if you follow the implications of such a notion of simultaneity, you can see why some people have made the assumption that reality is ontologically a static spacetime block where future and past exists all the time, and nothing moves except in some dualistic sense our "consciousness" (that assumption of "consciousness" is also just a consequence of trying to fit in our subjective experience coherently together with relativistic description of reality where time is a static dimension and nothing moves... ...which of course makes it immediately incoherent or at least very unelegant to suppose "consciousness" nevertheless moves over and beyond the control of "time", which was supposed to be the source of all motion!)

 

Also you should note that "length contraction" is a direct consequence of defining simultaneity as relative. That is simply because the geometry of an object must be defined as "where its extents are found at a single moment". Re-define what "single moment" means, you also redefine the geometry of that object.

 

Aaaand what follows is that if you take length contraction as ontologically real, you also take those simultaneity planes as ontologically real, and consequently you take clocks that move backwards in time as ontologically real... ...and that eventually forces you to take rather specific ontological view on time (as a static dimension), and creates rather specific constraints on your ontological view of your own subjective experience.

 

Anyhow, I should point out, if it wasn't obvious all along, that relativity doesn't allow for direct observation of any "simultaneity planes". It would never be possible to actually see clocks moving backwards or anything like that. We can measure some objects moving at different rates in different situation, but to explain that it is not necessary to suppose all of past and all of future exists all the time.

 

It is quite possible to arrive to the same observable predictions even if you define simultaneity as absolute, as long as you define other things in your worldview appropriately as well. (A simple way to see that this is indeed possible is to imagine a static spacetime block and just choose any arbitrary simultaneity plane as "absolute"... ...nothing inside that spacetime block is affected, just the way you describe things becomes very complicated if this is the only change you make on your worldview)

 

I am aware of few other ontological takes on relativity of simultaneity (or on "reality of the now-moment"), some more coherent than the others. I have no idea how many people here take see static spacetime as ontologically real. The actual reason I am bringing all this up is not to argue the ontological validity of one or the other view, but just to once again point out how these things have everything to do with how we define things in our personal model of reality. Just an attempt to open up your minds to see how one assumption constraints other assumptions and vice versa. (That's why I said "let's see if you can analyze your thoughts objectively" :)

 

Modest, in case you are wondering, that has got very little to do with the math of relativity. It just has to do with what kind of reality that math implies (or what sorts of realitites are still possible behind that math, many of which are not very evident from the math directly)

 

-Anssi