What is time?

[steve 9]

Originally Posted by modest

I'll point out for anyone that is not familiar with steve 9, that his intention is to argue from the premise of a false dichotomy. He has carried this over from other forums that have come quickly to the conclusion that he is a troll.

His questions are of the form: either time is a real physical thing or not. Because real is not equivalent to physical there is no simple yes / no answer to his question. Yet steve will resist any attempt to rephrase the question or give more than a black and white yes / no answer as Craig just did. Notice from steve's post above:



Here time is either a "physical thing" (which of course it is not) or it's "just a concept". This is the very definition of a false dichotomy or false dilemma. Any detailed exploration of what time really is (such as I tried in post #330) is rejected by steve out of hand and goes nowhere.

~modest

I ask if time is a physical thing or not. Simple question. You have said that time is not a physical thing, good, this is a start. So we can all agree that time is real to us, so the question is in what way does time exist for us? You have complained about this false dichotomy before, If you do not like the choices that I have given, or disagree with the way I have worded my question, then by all means do not feel confined to just my choices.

I say time is just a consideration, you disagree with this. You say time is not physical, great, so what is it?

Don't worry about how I have presented my questions regarding time. I just presented my questions in a way to get the conversation going.

Think about it, for something to exist for us it is either a physical thing or a consideration, in my opinion. If you know of a different way in which something can exist for us then let me know.

I am giving you full freedom to explain in what way you think time can exist.

You disagree that it is just a human consideration, O.K.
You say time is not physical, O.K

Now we are getting it narrowed down. So you have stated what time IS NOT. So can you state what time IS?

Enough with the protest about this false dichotomy business. I just posed a question to get the ball rolling, if you do not like the way it was posed then just come up with some scientific evidence that provides some data that time is more than just a consideration.

I have asked many times on this thread for any science that states time is something that exists in the physical universe. No one has provided any evidence of this.

Just to drive the point home.

Here is another black and white question.

Is there any scientific evidence that clearly provides data (any reference, observation, experiment) that states time is something that exist in some form in this universe? Y/N

You say time is not a consideration, you say time is not physical, you are almost there, just take that last step and say what time is. Of the ways in which you think that things can exist for us or be real to us, in what way do you think time exists?

This is a very simple question to resolve.

Is time physical? You say no.

Is time a consideration? You say no.

(Here is where you can provide another way in which you think something can exist or be real for us)

Please, I do not want to be accused of placing you in a position of having to only choose between what you consider a false dichotomy. You are free to come up with another option.

This should make it easier for you to simply state what time is.

You know if I am wrong about my view on what time is there should be some scientific evidence that you can provide that shows I am wrong, don't you think?

[steve 9]

Originally Posted by Overdog

In case your wondering what the problem is, I think it's this.



Scientific Realism (Stanford Encyclopedia of Philosophy)

Thank you for imput. If I was to simply sum up what you were trying to say, are you suggesting that time is a theory?

[dkv]

Given an object how do we associate time to it such that it can measured in any random coordinates system?
That will give you the answer.

[dkv]

actually time vanishes as there is an increase in the entropy.

[steve 9]

Originally Posted by CraigD

Steve9, what do you hope to accomplish by repeatedly, and without increased qualification and specificity, asking “what is time”? What value is what you hope to accomplish to anything that I, or any other user of physics, do when using physics?

It would be much easier to understand what you are asking, if you would explain why you are asking it. Judging by the many objections to your approach in asking your question, many others find your approach bizarre, un-useful, and annoying. If you would explain why you are asking “what is time?”, your questions might be greeted with more enthusiasm.

Fair enough, point taken. I will take your suggestion and approach this from a different angle. I will take some time to think about what you have said and get back to you. Thanks.

[Overdog]

Originally Posted by modest

Uh... are you sure you read what I wrote?

Real change requires real movement. Nothing can change without moving. No example can be given otherwise.

Real movement requires real time. Nothing can move without time. No example can be given otherwise.

~modest

PS - change is not a basic physics concept. Change is how humans think of movement. The more fundamental of the two is movement. More fundamental than movement is space and time.

Time, Distance, and Mass are the fundamental units of physics.

I think I did. But did you understand my question was "How can you Know"?

Ok, let me try to explain what I and some others are saying.

Lets take Plato's definition of Knowledge as Justified, True, Belief.

Epistemology - Wikipedia, the free encyclopedia

You've got the Belief part, and you've given excellent Justification. All that now stands in the way of an assertion that time has objective reality is the True part.

And this is where we run into a problem, because whatever time is, we can't observe it under a microscope. And the excerpt I posted from the Stanford Philosophy of Science site says knowledge of unobserved phenomenon is impossible.

How can we get around this? How can we Know time has objective reality?

EDIT:

Or did I misconstrue/misunderstand what you were saying?

[ldsoftwaresteve]

Originally Posted by modest

I think a good example of change is radioactive decay. For example, if we have a sample of carbon and we measure how much carbon-14 is in it then we can predict how quickly the C-14 will turn into nitrogen. It's a very basic process in nature that happens at a predictable rate. One gram of C-14 will be half a gram in 5730 years.

So, change is a good word to describe what's happening. Certainly carbon is changing into nitrogen via beta decay. But, change is incomplete. It doesn't completely describe the situation. Saying one gram of C-14 changes into a half a gram of C-14 is not the whole story. For the whole story we have to say how quickly it changes, how much time it takes to change.

So, it's not so much that time 'drives' change. It's more that change is meaningless without time. Consider change in position. Let's say there is a ruler that is one meter long lying on a lab table. We roll a ball from the zero position to the 100 centimeter position. So then:

Change = 1 meter

I wouldn't say time drove that change or caused that change. But I would say there is no way to discuss how fast the ball went without a very real process of the universe called time. Speed is change in position divided by change in time. If it took the ball one second to change position then the ball moved at one meter per second.

Change requires both space and time - two dimensions. It is impossible to describe change without both. So, time is not just a human concept. It is a human concept that describes something real about the universe.

~modest

You make good points. Especially about change being meaningless without time to describe it and I think I agree with you completely. Time is our way of understanding and giving meaning to change. The 'something real about the universe' is that change appears to be constant and one kind of change can be compared to another kind of change. That implies that all changes have a common cause, a common motive force.

The laws of physics are our identifications of how things act. Whether it's regarding motion or mass or chemical reactions or radioactive decay, what would be wonderful is to find a common cause for all of it. So far we haven't. Time has been the placeholder for the cause.

The ingenuity of man is such that we can work with flawed theories and don't need to change them as long as they work. When they don't work, then we change them. There really isn't much impetus to change when we can work within our current framework.

If there is value in this discussion, it's in questioning the concept of time - a very important part of our current framework. Personally, I think it stops us from seeing change in a different light. It takes an act of will to step outside our framework and consider change without time associated with it or at least to consider the cause of change that way.

Let's assume two things for the sake of argument. 1. there is a common cause for all changes. 2. that change is constant.

The problem with lumping all changes together in my previous statement is that there seems to be two kinds of changes that might not be related: changes in material structures and changes in position.

The concept of time allows us to bring these two kinds of changes together under its umbrella. Perhaps that has clouded our understanding. If we take 'time' out of the focus, we have two kinds of changes to account for and perhaps it's an easier starting point.

What if we say that chemical reactions and motion have nothing in common? Ultimately they might, but for now why not assume they don't. Just for grins. It could be that all motion was initially caused by a chemical reaction. That would make all change, including positional changes, relative to physical structural change. And for the moment, let's leave 'space' out of the focus too as it might muddy the waters so to speak.

Ok then, what drives chemical reactions? What drives change to take place at the smallest levels? What makes an electron fly around the nucleus of an atom? What is driving that stuff if it isn't time?

If everything that takes place happens because our universe started with a big bang, it would seem that the total 'energy' in the universe would be constant and would eventually run down and stabilize (assuming that all matter attempts to reach a state of equilibrium). Why hasn't it? Or are we operating on the assumption that it is running down? What if it isn't? Then we'd need to know where the motive force is coming from and what is driving the universe of change.

If it's not time and it's not magic, what is it?

[AnssiH]

Originally Posted by modest

No need to correct him. Ross isn’t talking about interpreting math. The “conceptual interpretation” refers to the theory or model.

Judging from the quote you pasted, I believe he is saying that "just because the math works, it doesn't mean it captures how reality is." He went on to say "each theory contains a conceptual interpretation that assigns meaning to its mathematical expressions". That is somewhat ambiguous statement; it could be interpreted as claiming that the conceptual interpretation suddenly does capture how reality is. And that would obviously not be a justified assertion at all. That is why I pointed out; "The mathematical form of each theory can be "conceptually interpreted" in a multitude of different ways"

In this context it is completely meaningless what was in the mind of the person who formed the theory in the first place, because his view of reality is also a semantical model, just like everybody else's. The math describes the behaviour of "semantically" defined entities.

Yes, only one ontology of space and time are correct to our universe. That, at least, sounds sensible to me.

Well, here I think I need to probe little bit to see where you stand.

Even if there is one "correct" way to define time and space - i.e. correct in that it perfectly coincides with the way time and space are metaphysically - do you think we would be able to find out? Considering that each definition contains a lot of unobservable features. (Note here that I include the ontological assumptions as part of our "definition of time and space")

Do you think it can be ontologically valid to identify some patterns ("objects") of reality as "ontologically same" from one moment to the next? (any definition of space requires you to do this for many patterns)
If it can be valid, do you think we could find out whether our definitions happen to coincide with some "ontological identity of things"?

You may be still using the word "ontology" differently than I do, and I may be reading you wrong, but it does seem to me like there are quite a few naive realistic assumptions in your thinking. So I thought I should remind you that my perspective on this is that the worldview - where the definitions for time & space exist - is something that is used to interpret a "data stream". I.e. the data coming from sensory organs is not metaphysically pictures and sounds; it's data to be interpreted as pictures and sounds (according to what the meaning of our sensory data is believed to be). Any aspect of that interpretation that you take as ontologically real amounts to a belief.

Hence any definition of space has to do with how some patterns have been identified in that stream. Whatever "space" means is largely a semantical issue.

As an interesting side note, all human communication includes a component of ambiguity exactly because of this reason; we all interpret each others according to our very own worldview... ...human communication becomes very tricky when we don't share the same paradigms. We are often so convinced of the validity of our own worldview that we don't think it's even possible to interpret the other person intelligibly... Like Kuhn said, one paradigm cannot be investigated from another.

Additionally I should mention that DD's epistemological analysis has to do with that same perspective; that we do not know anything about reality, but somehow we infer the meaning from completely unknown data. The investigation of "how that data can be modelled" has to do with certain symmetries that must exist in our view on that data exactly because we do not know what is its "ontological origin", so to speak. Certain interesting requirements for our models of time and space arise.

Admittedly this is somewhat tricky issue to communicate clearly when the other party is using different terminology and looks at reality somewhat differently. It's kind of like trying to explain to someone pre-Newton how a spaceship from Earth to Mars cannot really be said to "fly through space", apart from our conception of the situation. Certainly that person would take that assertion as clearly invalid, since he can clearly see the spaceship flying through space... ...the point is to concentrate on what semantical matters there exists. Like, is it Mars flying through space rather than the spaceship? And then to realize just what do we mean by "space" and what does it mean to "fly through it" etc... To see just to what extent human definitions give rise to our conception of reality.

Look at the spactime separation formula. There is already meaning there. dS and dT already have a definition in that formula - you can't just interpret it any way you like.

You can make a multitude of ontological intepretations that conform to the predictable observations, because here the ontological interpretations are the assumptions regarding what happens behind our observations. Just like is the case with the different interpretations of QM.

The assumption that reality is a static spacetime block is just one interpretation.

Another would be that reality does not exist in any definite "now-state" before it is being observed.

Or one could imagine each inertial frame is part of a multiverse, i.e. we switch to a different "space" (where the "now"-states really exist differently from each others)

I would imagine, that in the middle of assumptions as far fetched as any of the above, one would be somewhat motivated to investigate the possibility that relativistic time relationships arise from our ways of defining reality rather than from these ontological options. I.e. take a look at that epistemological analysis.

The fact that different frames measure a different frequency for the same source of light is key to relativity. Frequency is per unit time and time is relative. This shows how Einstein derived gravitational redshift which demonstrates. You are confusing variables with laws of physics. All laws of physics are postulated to be the same in all inertial reference frames - not just the speed of light.

I said it is a semantical issue what is considered a variable and what is considered "law of physics". We created the definitions that lead us to such and such laws for those semantically defined entities. I think your comment "you are confusing variables with laws of physics" just shows that you assume the "laws of physics" and "parameters" are ontologically real, embedded somewhere in metaphysical reality rather looking at them as "tools of predicting reality".

Despite what you said, I can prove time dilation is more than "just mental construction" - of course. Something that's just a mental construction has no basis of fact in reality. Unless you're arguing from an entirely phenomenalistic point of view then time dilation has real effects. A person on a mountain ages faster.

Do you really think I was claiming that time dilation does not happen? I was just saying that in order for us to understand something as "time dilation", we had to define quite a few things in our worldview that way, and that there are always many possible paradigms that we could use the understand the same situation. Both would be just as valid predictionwise, and neither can be defended to be more real ontologically.

Relativity is not a model. I normally wouldn't correct that, but it's important in the context of this discussion.

Interesting; I would have said the exact opposite for the exact same reason; in the context of this discussion is important to understand just how relativity is a model. Perhaps I don't understand how you mean your assertion, or perhaps you have a naive realistic view on relativity. Well, in any case it would be interesting to know whether you abide to the "static spacetime block" view of relativity, or whether you have even thought about what reality might look like behind the math?

Perhaps it is helpful to know that I am coming at this largely from the angle of General Semantics;
General semantics - Wikipedia, the free encyclopedia

Also I noticed the Wikipedia page for "Metaphysics" includes "Space and time" section which includes metaphysical questions of space that just reveal some of those semantical aspects regarding how we understand time and space;
Metaphysics - Wikipedia, the free encyclopedia

I skipped few things because I didn't think they were very relevant. If you want a comment on something I've skipped, just ask.

-Anssi

[AnssiH]

Originally Posted by steve 9

Take a stand. Just tell us what you think time is. Is it like matter? Is it like energy? Start somewhere and build your case.

I'm not sure if anyone disagrees with you about time being a concept. I mean we have just been talking about what sorts of features we attach to "time" in our conception of reality, and whether we can always define (~conceptualize) time in many valid ways to explain our subjective experiences.

But I think there are few communication failures in your conversations with others. I think when people insist time is nevertheless "real", they may be only saying that there must be something in objective reality that makes a concept like "time" valid for interpreting reality... ...without really taking a stance what that might be.

When I read your posts, it only occurs to me that since you have thought about purely conceptual aspects of the definition of "time" so much, you might want to consider what conceptual aspects there is in, say, definition of "matter".

-Anssi

[AnssiH]

Originally Posted by modest

PS - change is not a basic physics concept. Change is how humans think of movement. The more fundamental of the two is movement. More fundamental than movement is space and time.

That is entirely a belief, spoken from your personal worldview. There is no objective justification in the claim that one is more fundamental than the other, as you are merely talking about concepts that are defined in terms of each others.

Change requires both space and time - two dimensions. It is impossible to describe change without both.

It is impossible to describe "time" without change. One can say "there's no time if nothing moves/changes in the universe".

That is because if there is a universe where nothing moves, there is nothing to hang any definition of "time" to; time cannot be defined/conceived in any valid way at all!

(and btw, from the point of view of explaining completely unknown stream of data, "change" is what makes the definition of motion & time possible... ...but that really says nothing about the real ontological reality)

The matter of the fact is that concepts like "movement", "time" & "change", are associated with each others; they are all understood against each others. That is why we can say "one cannot exist without another".

The reason why you should not say "nothing can move without time" is that it implies time is something that is moving forward in some sense even when absolutely NOTHING else is in the universe; it implies a completely naive realistic view of time. (The alternative view (only semantically different) is that motion/change exists fundamentally - without cause - and gives rise to the definition of time)

Speed is change in position divided by change in time. If it took the ball one second to change position then the ball moved at one meter per second.

Or it managed to move "one meter" while another apparatus managed to move its thin handle by 6 degrees. Just underlying the fact that "second" is not measurable by itself; what we see is how objects change around us in relation to each others. We cannot see any "rate" of time in any objective sense.

-Anssi