pears

My point about the unicorn post was not related to my question to you. I had intended for them to go in separate posts but they were merged, which perhaps made who I was addressing and about what, unclear.

I was wondering that too. I assumed the answer was going to be some kind punchline...

No the original point was that the Bible states that unicorns are real, not that it mentions them. Quite possibly. How do we know this? Do we have multiple universes to compare against? What is the justification for this statement. Does it show that this universe is not influenced by a supernatural presence? What is the point of this exchange in relation to the topic title?

Those are really cool. The GDP map is one of my favourites

Thank you for putting me out of my misery

Well indeed. But then this whole thread is more of a philosophical discussion than a scientific one. Can a question such as "What is time?" even be answered by science?

I'm not postulating that. I've only postulated that when there is no motion in the universe as a whole then time could be thought of as not flowing. In your atom cloud, there may be no motion between the atoms but there would be some inside the atoms. I suppose if you stopped all motion in a region of space, including an atomic clock by pressing a magic button, the clock would stop ticking and time would appear to not flow. I guess the question is, what is the nature of the magic button? Is it a motion stopper or a time stopper, or do they amount to the same thing? I hadn't actually contemplated the cease of motion in an isolated region. I fear it may be too much for my brain to handle at this stage.

I know that. That's why I used the word hypothetical. It's a thought experiment to demonstrate my point that when there is no relative motion in the universe, then it is quite feasible to conclude that time is not flowing.

Hi I'm new too. I just wanted to say this site is really cool - it's a rare to find a place to while away hours on the internet without feeling you've just wasted time.

I remember this story. It's really cool, like the clockwork radio only more useful and accessible. Do you mean micro-funding initiatives for things like this? Like niftly little altruistic science research projects? If so could you provide me with more information please as that sounds so interesting

Why would you expect to observe time in this way? In what sense would you expect to observe it? The inference of time as a dimension fits in well with our understanding of the universe. Just because it is not directly observable in the way you suggest, (i.e. as if it were a material object) does not mean the model is wrong. Then it is pure speculation either way. In what sense can something that cannot be measured or observed in any way be said to exist - or not? Ah I see what you mean. But speed and motion are relative, so there is not absolute value of stationary. It can only be stationary relative to the observer, for whom the clock is running apparently normally. But if the clock ran slowly then so would the internal clock in the observer (i.e their aging process and their internal mechanism for perceiving time). So they would see time running normally, but another observer, with another clock, and biochemical system, would run differently, relative to the first observer. If all processes in the universe stopped, all observers at all points would perceive time running normally at their frozen instant of time (relative to them) but were there a hypothetical outside observer, outside of the universe, observing the frozen universe, they could conclude that time had stopped there. I see thank you, though presumably when you say 'truly at rest' you mean relative to the observer?

Shouldn't that be 001101? Sorry to be such a pedant but it's driving me crazy. Or am I wrong? I'm tired and really ought to go to sleep.

This is what I suspected but as a 'lay' person I wasn't sure. I'm interested in understanding the boundaries of scientific understanding. Thanks everyone for your replies.

Motion is a relationship between space and time. It describes the change in position of an object in space, with respect to time. You cannot describe motion without reference to time. But the concepts of motion and time do seem to be bound up together. If all motion in the universe ceases then can time really be said to be passing in any meaningful way? If there was no motion, there would be no pendulums, no oscillations in atomic clocks, no biological processes such as aging, or conscious awareness of the passing of time, and no change in the entropy of the universe. So a universe with no motion would be indistinguishable from a universe where time had stopped. Could the flow of time really be said to exist in such a static universe? So it seems that in some way time, or at least the idea of time as a flow does depend on the concept of motion, or at least on the concept of change. But then as time depends on motion for its definition, so does motion depend on time. You cannot discuss the one without discussing the other, as in the Opening Poster's experiments 1 and 3 demonstrate: So to a certain extent I do agree with the OP that time (or the apparent flow of time) depends on motions or physical changes, however I think that as time is dependent on motion, so motion is dependent on time to have any possible meaning. But if all motions and changes in the universe ceased, how could you possibly know if time was flowing? Also what do you mean that the rate of time passing is greatest when there is no motion? I am out of my depth with your second sentence (well I am possibly out of my depth in the whole discussion but anyway...). What does it mean for motion to go fuzzy at the QM level? But regardless, I assume some changes are still occurring at the QM level when time is 'flowing', which is I suppose is what Daniel ultimately means when he talks of motion. At least that is what I mean when I think of the flow of time being dependent on motion. Can you tell me more about this real or absolute time? I read the wikipedia article but couldn't find much more about it after a quick google (maybe I'm searching for the wrong things) How can its existence be demonstrated?

Yes - we, the observer, experience time like it's passing over us. But 'it' does not necessarily 'flow'. More we move through it. I don't know - maybe it's just a you say to-may-to I say to-mar-to thing. True. I was just trying to visualise the idea as expressed in the OP as I struggle with the idea of time flowing, stopping, then running forwards again, without somehow stepping outside of time into another type of more absolute time. I suppose what I'm really trying to say is yes, everything would turn out the same, because I don't view time in that sense, as running backwards and forwards like that.

But does time actually 'run' at all? I understand there is an arrow of time which gives it a direction, but isn't time itself a plane through which things pass in a particular direction as opposed to something that flows over us? If things were to move backwards through it, if we were to move backwards through it, wouldn't our internal clock that gives us our sense of time, actually go in reverse? So would we even notice the difference? Trying to imagine time at first 'stopping' and then changing direction, twice, requires one to step outside of time while still maintaining a sense of time - i.e. my use of words such as first, and then - almost as if one steps from our finite space-time into eternal or absolute time. I'm unable to this idea of time stopping, and then running backwards, and then forwards, with any coherent meaning, at least in the realms of natural physics. However, I could picture space-time as a sheet through which something, a point, (or indeed everything - a line) passes along it in the past to future direction, and then the point or line changes direction and moves backwards for a bit (without necessarily any awareness it has done so) and then moves forwards into a new branch of the sheet. The 'old' future (yes struggling with language here) is still there, it has not ceased to exist, but the point or line on the space-time sheet is now passing through a different plane. This is how I would visualise or express the idea in the OP. I hope that made sense! Does wave-function collapse give an arrow of time at the quantum level? That was hinted at at the wikipedia article. I haven't heard of these. I'll look them up!

What kind of rubbish?

Does time actually 'flow' in this way at all from the pov of physics? Isn't time just a 'space' for want of a better word, and the present just a point in that space? Sure time appears to 'flow' from an individual conscious mind perspective, but can it actually 'go' forward and backward like this?

Surely we assign probabilities to unknowns? What is the point of assigning a probability to a known past event? Isn't that meaningless? Isn't the fine tuning argument is about asking what are the odds that the universe is the way it is, that the fundamental constants beyond some boundary where they are known, could have become what they are? Unless by assigning 100% to the odds of us being here you mean it was inevitable, that there was no possible other way the universe could ever have been other that it is, which is quite a claim.

Oops sorry! It was intended as a joke not an insult. I apologise if I caused offence to anyone.

Interesting. I guess there is no way of ever truly knowing. I don't know much about amoeba, (or ants come to that) Do they (amoeba) seek out food because they are hungry? However I take your point - need does not necessarily imply consciousness. I don't believe plants are conscious, and they need water. But for a robot to utilize need as an aid to learning, would that not require some level of awareness? Otherwise how would it work?

Does need require consciousness? It's a felt experience isn't it?

I think somebody's been smoking too much of the green stuff...

It's either a very bad program or a very stupid person.

Oh ok. Thanks - I guess I don't know much about gravity I think I need to brush up my physics!