Define time.

#1
A colleague and I were discussing its nebulous nature.

Human construct, yeah. But does measurement of its "passing" do anything more than demarcate our own expiry?

I think adherence to a universal standard here is born of fear—rather than efficiency—to be honest with you.

So, I asked this guy to define it in eight words, and here's what he came up with:

"perceived change based on memories of prior events"
This sounds vaguely familiar, but can't quite place it.

Anyone got something better?

 
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#3
Some say that time is merely a human contrivance. Others have indicated that time is merely nature's way of keeping everything from happening at once (whereas space is its way of keeping it all happening at the same spot).
Interesting theories.

Which is it for you?

If it's the latter ("nature's way..."), was this taking place prior to primates evolving a particular level of cognitive capacity...? Was it "elapsing" without recognition, so to speak?

If there's no beginning and no end, can it even exist in the abstract?
 
#4
A colleague and I were discussing its nebulous nature.

Human construct, yeah. But does measurement of its "passing" do anything more than demarcate our own expiry?

I think adherence to a universal standard here is borne of fear—rather than efficiency—to be honest with you.

So, I asked this guy to define it in eight words, and here's what he came up with:

"perceived change based on memories of prior events"
This sounds vaguely familiar, but can't quite place it.
Maybe you're thinking of that book by Proust, "Remembrance of Things Past"?
 
#5
Some say that time is merely a human contrivance. Others have indicated that time is merely nature's way of keeping everything from happening at once (whereas space is its way of keeping it all happening at the same spot).
AntiSabooshian poppycock! Inside The Vortex, a very bland place with no boundaries, there is no thyme to spice up our poor existences.
 

Sentinel

Bionic Poster
#8
Some say that time is merely a human contrivance. Others have indicated that time is merely nature's way of keeping everything from happening at once (whereas space is its way of keeping it all happening at the same spot).
From where I come, it has been said that everything actually does happen at the same time. I can't recall the source, or whether it is just some self-proclaimed mystic or some established scripture.
 

Sentinel

Bionic Poster
#9
Sometimes I just wish I could reach out and touch those moments long gone, when I was a kid and my parents were young. Those moments when I could run tirelessly.

This universe and time are both in the mind. They are a part of the grand illusion.
 
#10
A colleague and I were discussing its nebulous nature.

Human construct, yeah. But does measurement of its "passing" do anything more than demarcate our own expiry?

I think adherence to a universal standard here is borne of fear—rather than efficiency—to be honest with you.

So, I asked this guy to define it in eight words, and here's what he came up with:

"perceived change based on memories of prior events"
This sounds vaguely familiar, but can't quite place it.

Anyone got something better?

Yes time is a human construct and what I think you’re seeing is the byproduct of entropy
Time gives us rules and stability but it does not exist in the way we think
 
#11
Interesting theories.

Which is it for you?

If it's the latter ("nature's way..."), was this taking place prior to primates evolving a particular level of cognitive capacity...? Was it "elapsing" without recognition, so to speak?

If there's no beginning and no end, can it even exist in the abstract?
Our universe has a beg and end and their were infinite worlds before our universe came into being over 14 billion yrs
Lisa launch in 2034 will prove other universes before ours
 
#12
Entropy runs in the reverse in other universes
So maybe you’re born and look like a very old man but you become younger each year . Maybe in this world : eggs don’t break and things don’t scratch and breakdown as the entropy river runs away from the current
 
#13
Interesting theories.

Which is it for you?

If it's the latter ("nature's way..."), was this taking place prior to primates evolving a particular level of cognitive capacity...? Was it "elapsing" without recognition, so to speak?

If there's no beginning and no end, can it even exist in the abstract?
To my mind, time is an illusion. I'd have more to say about this, but I just don't have the time to spend on it. Furthermore, I'm late for something... id est, the rest of my life.
 
#20
I think of time as a physical phenomenon independent of our perceptions. From this perspective a succinct if not dry definition could be something like time is that which passes from present to future.

Appreciating all the while the many theories, philosophies, and other studies fill volumes, anything more than the above definition would serve only to describe its properties and our perceptions.

In science time is t.
An expression for time
 

sureshs

Bionic Poster
#21
I think of time as a physical phenomenon independent of our perceptions. From this perspective a succinct if not dry definition could be something like time is that which passes from present to future.

Appreciating all the while the many theories, philosophies, and other studies fill volumes, anything more than the above definition would serve only to describe its properties and our perceptions.

In science time is t.
An expression for time
Circular reasoning. Present and future are ideas from the arrow of time. You can't use them back to define time.

Also, if time is discrete with the smallest unit being Plank's time, integration is not valid (assumes continuous function)
 
#28
I think of time as a physical phenomenon independent of our perceptions. From this perspective a succinct if not dry definition could be something like time is that which passes from present to future.

Appreciating all the while the many theories, philosophies, and other studies fill volumes, anything more than the above definition would serve only to describe its properties and our perceptions.

In science time is t.
An expression for time
Is time necessarily a physical phenomenon?

I think of it as an entity that exists merely as an agreed upon notion.

Separately, an issue I have with the "that which passes from present to future" definition is that present and future are both time-dependent entities, themselves.
 
#29
@BarNotchky @FedFosterWallace
Circular reasoning. Present and future are ideas from the arrow of time. You can't use them back to define time.

Also, if time is discrete with the smallest unit being Plank's time, integration is not valid (assumes continuous function)
I would think it irony rather than circular reasoning.

How does Plank's time compare to Planck time? It was fairly well know that Planck was habitually late... no doubt cuz he was on Planck time. Inferior pocket watch?
 

sureshs

Bionic Poster
#30
Is time necessarily a physical phenomenon?

I think of it as an entity that exists merely as an agreed upon notion.

Separately, an issue I have with the "that which passes from present to future" definition is that present and future are both time-dependent entities, themselves.
Yeah I already pointed that out. It is like saying Nadal is better than Federer because Federer is worse than Nadal.
 
#31
Yeah I already pointed that out. It is like saying Nadal is better than Federer because Federer is worse than Nadal.
Post to which I replied felt like a "teaser" to me; like there was/is more to follow.

Depending on the level of comprehension.

Hope there is more to follow.

I don't disagree with your "circular" evaluation. But (correct me if I am wrong) I don't believe you addressed the poster's characterization of time as a physical phenomenon. Glaring problem, no?
 

Bartelby

Talk Tennis Guru
#32
There is an article up on BBC, I think, about memories of first events, which suggests that memories are memories of past memories.

I suppose that means we are always dealing with 'updates' with no access to the original state. This must have consequences for our concept of time.

So, I asked this guy to define it in eight words, and here's what he came up with: όrt

"perceived change based on memories of prior events"
This sounds vaguely familiar, but can't quite place it.

Anyone got something better?
 

sureshs

Bionic Poster
#33
Post to which I replied felt like a "teaser" to me; like there was/is more to follow.

Depending on the level of comprehension.

Hope there is more to follow.

I don't disagree with your "circular" evaluation. But (correct me if I am wrong) I don't believe you addressed the poster's characterization of time as a physical phenomenon. Glaring problem, no?
I will tell you in due time
 
#35
There is an article up on BBC, I think, about memories of first events, which suggests that memories are memories of past memories.

I suppose that means we are always dealing with 'updates' with no access to the original state. This must have consequences for our concept of time.
I'm superficially familiar with some of the theories about the universe being naught but a holographic projection, and such.

But it really does seem as if something kindled from deep in the human consciousness has produced this elaborate web. I have a hard time envisioning it as something beyond our imagining.
 
#37
Yeah I already pointed that out. It is like saying Nadal is better than Federer because Federer is worse than Nadal.
Yes, the fallacy is apparent here. It should be: Federer is better than Nadal, cuz Nadal is worse than Federer. In TIME you also will come to know this. And realize how truly profound the statement is.
 

TnsGuru

Professional
#39
Perspective on time is different as a child vs an adult. I remember as a kid I would be in class watching the clock and it would seem like time was in slow motion and an hour seemed like an eternity to me. As an adult time just zips by so quickly it seems like an hour means nothing.

The older I get time flies by more quickly, I wonder if there is a way to trick your brain into slowing things down and make time last. The faster time goes by means I'm that much closer to expiration. :unsure:
 
#40
Perspective on time is different as a child vs an adult. I remember as a kid I would be in class watching the clock and it would seem like time was in slow motion and an hour seemed like an eternity to me. As an adult time just zips by so quickly it seems like an hour means nothing.

The older I get time flies by more quickly, I wonder if there is a way to trick your brain into slowing things down and make time last. The faster time goes by means I'm that much closer to expiration. :unsure:
Really good points.

And the very fact that we have the capability to "bend" time or to make time "stand still" through mental gymnastics supports the argument that it doesn't exist outside of our own minds. At least time as perceived by an individual.
 
#41
Is time necessarily a physical phenomenon?
Short answer, I'd say no. The dilemma stems from semantics. We're arguing over distinct but very real uses of the word time.

Time as a physical phenomenon
  • This is the time in which the physical laws of nature exist and evolve. For example the energy states of a cesium 133 atom transition at a precise rate over time (if this were not the case your GPS would not work)
Time as a human experience
  • This is the time that seems to take forever when we're bored and flies by when we're trying to catch up on sleep
Both are real, both are valid, and they're surely distinct from one another. We just have to agree which we're discussing.

Separately, an issue I have with the "that which passes from present to future" definition is that present and future are both time-dependent entities, themselves.
In this oversimplified definition the terms present and future are used as inputs and outputs to the notion of time as an operator which takes present and produces future. There's a subtle difference between defining something by restating it and defining an operation that operates on itself.

Perhaps I'm actually defining a "timenator", an operator that generates the future out of the present. Hey what did you expect in 10 words or less?

 

sureshs

Bionic Poster
#42
Short answer, I'd say no. The dilemma stems from semantics. We're arguing over distinct but very real uses of the word time.

Time as a physical phenomenon
  • This is the time in which the physical laws of nature exist and evolve. For example the energy states of a cesium 133 atom transition at a precise rate over time (if this were not the case your GPS would not work)
Time as a human experience
  • This is the time that seems to take forever when we're bored and flies by when we're trying to catch up on sleep
Both are real, both are valid, and they're surely distinct from one another. We just have to agree which we're discussing.



In this oversimplified definition the terms present and future are used as inputs and outputs to the notion of time as an operator which takes present and produces future. There's a subtle difference between defining something by restating it and defining an operation that operates on itself.

Perhaps I'm actually defining a "timenator", an operator that generates the future out of the present. Hey what did you expect in 10 words or less?

Non-physical (psychological) time is overrated. For example, the psychological distance to a place can appear different depending on things like: is it the first time, is something pleasant anticipated etc. Outbound and inbound journeys can appear to have different durations based on such factors - a trip back from Hawaii can seem longer than a trip to Hawaii full of eagerness. The distortion of distance can be attributed to the distortion of time.

These are just mental phenomena which are not fundamental in any way to Physics.
 

sureshs

Bionic Poster
#43
Einstein said time is what prevents everything from happening at once.

I thought it was a profound statement, but now I am thinking if it is really a circular argument, because "at once" implies the notion of time.
 

Northern

Hall of Fame
#46
Einstein said time is what prevents everything from happening at once.

I thought it was a profound statement, but now I am thinking if it is really a circular argument, because "at once" implies the notion of time.
I don't think what you say is true. What Einstein is actually saying is that if you don't have time, then all events collapse in that dimension. The same way as if you project a 3-dimensional object on a plane. Losing the z-axis means that all points of the object would be happening "at once" in the xy-plane. I think that is what he meant.
 

sureshs

Bionic Poster
#47
I don't think what you say is true. What Einstein is actually saying is that if you don't have time, then all events collapse in that dimension. The same way as if you project a 3-dimensional object on a plane. Losing the z-axis means that all points of the object would be happening "at once" in the xy-plane. I think that is what he meant.
That implies that time has an axis, like space. That is not clear at all because all fundamental equations are time-reversible - the backwards-running movie is as fully compatible with Physics as the forward one. It is only at a macro scale that there is an arrow, like breaking an egg. So if there is no arrow at a fundamental level, the comparison to spatial axes collapses. That is why I said it is a circular argument.

What he probably meant was that time is needed to enforce causality.
 

Northern

Hall of Fame
#48
That implies that time has an axis, like space. That is not clear at all because all fundamental equations are time-reversible - the backwards-running movie is as fully compatible with Physics as the forward one. It is only at a macro scale that there is an arrow, like breaking an egg. So if there is no arrow at a fundamental level, the comparison to spatial axes collapses. That is why I said it is a circular argument.

What he probably meant was that time is needed to enforce causality.
If there was no time then everything would happen at once, he wasn't talking about causality but obviously causality can't exist without time because in that case cause and effect would coexist simultaneously and no link between them could be established.

The axis is a construct to represent a dimension. Just because you can't satisfactorily represent a fourth dimension on paper it doesn't mean you can't associate time an "axis."

You lost me when you said that all fundamental equations are time-reversible. If you play a movie of the Universe backwards it will appear as if it is contracting. The same with electronic decay. I am not sure what you meant.
 

Enga

Hall of Fame
#49
Dunno if I read this somewhere or what but something tells me that time is like the universe "communicating" with itself. Similarly to how the neurons in the brain require nerve impulses to travel in certain patterns and sequences to create thought as we know it, the universe requires time in order to distribute energy the way it does. Like Einstein said, if there were no time, everything would be happening at once, or something. So there's not necessarily any reason for time I guess, just that time is kind of the cause of why the universe is the way it is. It could be a random rule for the universe that just so happens to benefit our way of living. If there is a design to the universe, then time is very necessary to create this physical world we can experience.

That's not to say that thought and experience isn't possible in universes where time doesn't exist, and the rules are different. It just so happens that it's necessary for our way of thought and experience.

I guess if I were to define time, it's a law, or a rule. Think of the universe as a big game or a program. Time is one of the rules that govern it, arbitrarily or not. Thing is definitions require meaning. There is not necessarily a meaning to time. You would have to ask God.
 
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sureshs

Bionic Poster
#50
If you play a movie of the Universe backwards it will appear as if it is contracting.
You need to understand what happened and what can happen. The Universe can be replayed back and it is called the Big Crunch. If it cannot, it due to MACRO causes related to entropy, which I mentioned before, like breaking an egg. And even that is possible to reverse with a very LOW probability.

All fundamental physics can run forwards and backwards without violating any Physics laws.

And causality can go backward in time. Read about Feynman diagrams in which events in the future can affect the past.

It is even possible to see that in classical Physics. Write Newton's second law in terms of second derivative of time. Replace t by -t. What happens? The sign inverts on the first derivative, but inverts again on the second, keeping the equation the same. That is what is meant by saying that fundamental Physics is the same with time reversal.
 
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