# Time as an illusion that arises from motion.

by CatAteMyHW
Tags: arises, illusion, motion, time
P: 8
Good-evening members!
For some time now, time is really bugging me. Especially this line in the Wikipedia entry on Time
 Time is used to define other quantities — such as velocity — so defining time in terms of such quantities would result in circularity of definition.
I came across this article that says that time is sort of an illusion created by motion of things in space.
So my question is, can we describe motion by using just motion and space - without using time?
To elaborate, suppose a body moves 10 meters in 10 seconds, can we instead write that the body moves 10 meters with speed 10V (V being fundamental unit of speed).
With that I'm starting to imagine the difficulties in explaining the processes that would be far easier if we just used time, for example describing heating of an object by using this logic would require taking into account velocities of particles and their motion through space, but they can be described this way... right?
 P: 789 Yes. What you are talking about is the way it is actually done. The speed of light is exactly 299,792,458 meters per second, by definition. No error bars, nothing after the decimal point. The second is then defined as exactly 9,192,631,770 periods of a line generated by a Cesium 133 atom. This is a very stable line, but not perfectly stable, so it will have some error associated with it. It follows that the meter is a derived quantity, equal to the distance that light travels in 1/299,792,458 second, a distance that has a certain error of measurement associated with it also.
 P: 8 Thanks for the input. Consider this.. Let's have a simpler clock used as a standard in relativistic time-dilation examples. Two parallel planks 1/299,792,458 of a meter apart with a photon oscillating between them. Now let's say you fire a photon and time the duration with that clock till it reaches a point exactly 299,792,458 meters away from the starting point. That's your 1 second, or 9,192,631,770 cycles of transition between two energy levels of the Cesium-133 atom, or 299,792,458 cycles of photon oscillating between those planks, right? And that's the "circularity of definition". You're measuring motion with motion. So lemme rephrase my question in a more direct way: is time just an illusion we feel due to motion of things (in our case motion of individual particles making us up) through space? And we use it just as a simple way to describe things? I should add that I'm novice in physics, but that should't stop me from asking questions, right? :)
P: 76

## Time as an illusion that arises from motion.

 Quote by CatAteMyHW So lemme rephrase my question in a more direct way: is time just an illusion we feel due to motion of things (in our case motion of individual particles making us up) through space? And we use it just as a simple way to describe things? :)
As a fellow novice, I question your choice of words; without motion there is no time, but time is used to describe events not things, and the events are real not illusions. The only real time is 'now' and historically time is a numerical record of a succession of 'nows' (movements).
P: 8
 Quote by jhmar As a fellow novice, I question your choice of words; without motion there is no time, but time is used to describe events not things, and the events are real not illusions. The only real time is 'now' and historically time is a numerical record of a succession of 'nows' (movements).
I've chosen words correctly... I think. Motion is always related to things (particles, bodies etc) and not events. You cannot move an event! A thing moves - that's an event (or a set of events). I would agree with "without motion there is no time". Infact that's my whole point.
Can you measure an event without motion? Writing this post, I cannot think of any (real or theoretical) apparatus that can measure time directly... like you can measure space directly - with a ruler - without motion. But to measure anything that you can describe with time (like temperature, current, velocity... and many other phenomenon i'm sure - which are all a form of motion) has to be measured with another motion!

Thanks for indulging in an argument, for understanding deep concepts like this I always prefer having arguments and/or discussions rather than reading up texts (though I wouldn't be reluctant to if someone could point me to it). Learning is an interactive process, right? :)
 P: 789 Measuring time intervals or space intervals ALWAYS involves the measurment of the time interval or space interval between two EVENTS. Particles are a bunch of events that are strung together, like a curve is a bunch of points strung together. If you measure the distance between two events, those events have to happen at the same time. You set your ruler's zero point at the first event, lined up with the second event, and when the events occur, you read off the distance, using moving photons that hit your eye. If you put two dots on a piece of paper, put your ruler's zero point on the first dot, line it up with the second and read off the distance, you are measuring the distance between two events that is not simultaneous, so you better have outside knowledge or faith that the second dot didn't move and the ruler didn't move between the time you placed the ruler's zero point on the first, and looked at the second. Again, distance must be measured between two simultaneous events. If you measure the time between two events, those events don't have to happen at the same place, in classical physics, but Einstein showed that they really do have to happen at the same place if things are moving near the speed of light. You could make a clock that does not have moving parts: You could make a clock out of a piece of fluorescent material. Put it under a light, then turn off the light, and wait till the brightness of the material dropped to half its value, that would be one tick of a clock that has no moving parts. When it dropped to half of that value, that would be another tick. To measure the time between two events that do not happen at the same place, like two firecrackers going off here and then later over there, you will have to use moving photons from the second firecracker to sense when it went off. In classical physics, your clock could be moving and still give the right time, but Einstein showed that, just like the ruler, it should not be moving (or moving very slowly compared to the speed of light) when you make the measurements. You cannot make any measurement without some moving parts, if only the photons that are moving to your eye to make you see what the result of the measurement is.
P: 90
 Quote by CatAteMyHW I would agree with "without motion there is no time". Infact that's my whole point.
I've heard that argument many times and I have never found it easy to agree with because:

If there is no time there can't hardly be any motion either can there... motion being displacement in time?

All that is left is space and displacement and no way of finding out how the displacement took place. At the races you'd have all the horses win because without time the term "fastest" doesn't make sense. Actually the horses would all be at every point on their route in arbitrary order. (Or maybe I'm wrong - "be" is probably a word that only makes sense if there is time - in which case they can't even be on the track.)

- Henrik
P: 448
 To elaborate, suppose a body moves 10 meters in 10 seconds, can we instead write that the body moves 10 meters with speed 10V (V being fundamental unit of speed).
Don't imagine you can.How do you describe V without using time.It's all very well saying V is the fundimental unit of speed but what does that actualy mean.How can you measure speed without time or some derivative of it.So you might as well use time it's less confuseing.
 P: 90 As I understand it nobody knows what time is. And the same can be said of space and energy. We never experience energy as such - only manifestations of energy when it behaves like a particle, like a field, like light, like a wave - or we can measure the relative differences in amounts of energy - hotter or colder - faster or slower - plus or minus - more or less impact and so on. We don't see the "something" that we call energy. Please correct me, if I'm wrong on this. - henrik
PF Gold
P: 10,766
 As I understand it nobody knows what time is. And the same can be said of space and energy. We never experience energy as such - only manifestations of energy when it behaves like a particle, like a field, like light, like a wave - or we can measure the relative differences in amounts of energy - hotter or colder - faster or slower - plus or minus - more or less impact and so on. We don't see the "something" that we call energy.
Energy is the ability of a system to produce changes in another physical system. It isn't some sort of invisible mystical force or really anything physical either. When a system changes another system, we call that a transfer of energy, or Work.

One could aslo claim that no one knows what distance is, or anything else because you have to describe using other terms. A light year is the distance that light travels in 1 year. So we have a distance described using time and the change in location of the light. A year is the amount of time that light travels 1 light year. Now we have time described by distance. The vibration of atoms in atomic clocks is a change in energy states over time. It is all interelated and unable to be separated or described without one or the other. Hence the term Spacetime.

At least thats my view on it.
P: 448
 Quote by Hernik As I understand it nobody knows what time is. And the same can be said of space and energy. We never experience energy as such - only manifestations of energy when it behaves like a particle, like a field, like light, like a wave - or we can measure the relative differences in amounts of energy - hotter or colder - faster or slower - plus or minus - more or less impact and so on. We don't see the "something" that we call energy. Please correct me, if I'm wrong on this. - henrik
Not sure if wrong is the right answer maybe a leaning towards the metaphysical rather than the actual physical.We could conclude that we never actualy experience anything touch, taste, distance, time, sight. all elaborate concoctions of the solopasistic mind.Surely physics is an attempt to try to understand, measure and to reach a consensus that is workable about our enviroment.
 Mentor P: 28,456 If this thread starts to veer into philosophy, it will be locked! If you can't produce a post that is based on physics, rather than just simply a personal opinion or based on personal tastes, then this is no longer physics and this thread is done. Zz.
 Sci Advisor PF Gold P: 1,767 My 2¢ worth, An "illusion" is a false perception of reality. This doesn't apply to time. Time is a parameter we use to order events. Events are real and their temporal separation is meaningful but the time parameter itself is a conceptual tool we utilized to express that reality. Similarly space is a conceptual entity we use to order the spatial separation of events and the chains of events we associate with objects. We do know what time is really and what distance is really where "really" means operationally (how it is used as a concept). Einstein articulated this very well "Time is what we read off of clocks and distance is what we read off of measuring rods." (And as Einstein also pointed out there are different times and distances when you consider different clocks and measuring rods.) In a scientific context the most fundamental definition is the operational one, (how we use it in experiments) so there's no further need to explain or define distance and duration. What is left is the observation and theoretical postulation of how time and distance behave which is the point of relativity experiments and theory.
P: 5
 Quote by CatAteMyHW I came across this article that says that time is sort of an illusion created by motion of things in space.
Because I wrote that article I thought I would participate.
You are right to say that I suggest that time is a mental illusion which origin is motion. But I want to mention that I do not suggest that motion occurs in space.
Space (in my opinion) is also a mental illusion.

 Quote by CatAteMyHW So my question is, can we describe motion by using just motion and space - without using time?
Why would you try to “describe motion” using space and time (which might be illusory) when physics (itself through Einstein) teaches that both time and space are functions of motion?

It is much simpler to consider motion is a physical entity.
And then to use (that physical entity) motion to describe everything else.
It turns out that using motion as a building block, one can describe everything else!
And that leads to a very simple unified interpretation of nature!

The only thing you do through such a process, is to replace two fictitious mysteries that are space and time by a physical mystery: motion!
P: 5
 Quote by Rap The second is then defined as exactly 9,192,631,770 periods of a line generated by a Cesium 133 atom. This is a very stable line, but not perfectly stable, so it will have some error associated with it. It follows that the meter is a derived quantity, equal to the distance that light travels in 1/299,792,458 second, a distance that has a certain error of measurement associated with it also.
The problem here is:
Because time depends on motion (time dilation), which by the way has been verified experimentally with such atomic clocks, the meter depends on motion.
Again its is much simpler (in my opinion) to use motion, which happens to appear everywhere, as a reference to describe anything else rather than anything else to describe motion.
P: 5
 Quote by Rap You could make a clock out of a piece of fluorescent material. Put it under a light, then turn off the light, and wait till the brightness of the material dropped to half its value, that would be one tick of a clock that has no moving parts.
Is dropping not moving? All changes occur through some sort of "physical" motion.
P: 5
 Quote by Hernik As I understand it nobody knows what time is. And the same can be said of space and energy. .... Please correct me, if I'm wrong on this.
You are absolutely right!
The funny thing is that on the other hand everybody knows what is motion!
Everybody experiences motion at all time.
Yet everybody ignores the reality of motion.
We human beings prefer to navigate within fictitious ideas than build up mental images of reality!
P: 448
 I suggest this answer: It is much simpler to consider motion is a physical entity. And then to use (that physical entity) motion to describe everything else. It turns out that using motion as a building block, one can describe everything else! And that leads to a very simple unified interpretation of nature! The only thing you do through such a process, is to replace two fictitious mysteries that are space and time by a physical mystery: motion!
Well go on then how do use motion to describe everything else.