Time surely is a virtual phenomenon, it's defined with atomic events. But it's defined, that's the point. With that definition we can define classical velocity and acceleration. I don't see any problems here. Maybe I didn't understand your point properly.

Time is neither a virtual phenomenon nor an illusion, at least within the theoretical framework of Physics. Time is as much real as space, matter, energy, etc. Time is one of the dimensions of the 4-D dimension Minkowski space-time continuum that for sure is real. The theory of relativity (general as well as special) essentially try to understand the personality of time along with space and their interplay with matter and energy. Time brings in all the dynamical changes in this universe at classical as well as quantum level. You remove the arrow of time, the velocity, acceleration, the energy-matter transformation, etc., cease to exist, the way you also realize the problem. Anyway the illusions, time clocks, perceptions are only for humans that appeared merely within the last ~2 million years. All the dynamical processes initiating from the beginning of this universe brought about all the changes only due to the flow of time. This would have happened even in our absence. The laws of thermodynamics also become redundant (just like other principles of Physics) in case you make time virtual. The basic tendency of any system to acquire higher entropy is essentially due to the flow of time.

@Sahijpal Could you show me the money? I mean that time which is as real as surrounding space ;-)

Whatever we perceive as time and time flow is actually recorded perceptions of consecutive events. These events are changes in states of physical phenomena around us, changes in location, color, shape, size, etc. so that if a change happens in an object in such a way that before it reaches its next state, we can perceive several other changes in the state of some other object we would say that second object is changing faster than first object, and that is where the concept of velocity is formed. When 9192631770 cycles of radiation corresponding to the transition between two energy levels of the caesium-133 atom happens we would say that one second is passed.

What I want to know is possibility of defining velocity and acceleration based on coincidence of events with a reference event, for instance, change of energy level of caesium-133 atom, changes in location of clock arms, or changes due to any other appropriate movement.

@Hassanali Velocity and acceleration as classical concepts are incompatible with your goal. However, in ToEbi (Theory of Everything by illusion) you can nail down a speed with events. ToEbi energy relation says that (delta f)=0.5* (delta v)^2, where f is particle spin frequency.

The best way to understand the concept of space and time is to understand the concepts of special and general theory of relativity, the concept of light cone, etc.

Please refer to any standard book.

Let me go further on my previous argument. Imagine a universe where there is nothing there. In this universe, the space as well as time become meaningless as there is no interaction. Now when you introduce matter (and energy) into this empty universe, the interaction sets in the form of either of the four forces. The space and time now become meaning full due to the dynamics introduced by the interaction. Even though, the perception of space and time are different for different observers (STR).

The statistical mechanics and thermodynamics are based on the concept of ensemble theory. In case you want to avoid understanding the time averaged behaviour of a system you can invoke in an ensemble average. An ensemble is essentially a set of multiple photocopies of a single system that are generated at a single time by randomizing the actual system to incorporate all possible likelyhoods that the system can go through over time. Please refer to any standard book on stat. Mech. I think that you have something like that going on in your mind.

Dear HR,

(1) The successive "nows" of Barbour only make up what we call time. So there is nothing like non-existence of time even in Barbour' scheme.

(2) Any Movement or change presupposes existence of time and thus we should not labor under the illusion that "time is illusory and (at the same time !) movement and change etc are real." Please See responses to my question on "transforming away time time in GR".

(3)We cannot have a timeless world. Timelessness means worldlessness. No time, no phenomena, no world.

Regards,

Rajat

Dear S Sahijpal,

To imagine an empty universe the imagining agent mind must be there first.. Do you mean to talk about an empty universe which exists in the mind only, without the mind first existing in the universe ? Or Is the imagining mind outside the empty universe that is imagined , in which case it is no longer a scientific proposal to be discussed further?

These are very tricky issues really.

If one can imagine a spaceless and timeless universe because in the absence of interactions these become meaningless, one could very well do just the opposite by imagining interactions to be arising only because of the existence of space and time as primary categories.

But as noted by you time and space appear differently to different observers thus they are subjective and hence cannot be objectively real like other phenomena. But phenomena also appear differently to different observers. Thus they cannot be real.

Thus the only logically acceptable statement is that," time,space, phenomena and hence the entire universe are illusions, none of them being more real than the rest."

This is what Vedanta philosophy teaches.

Regards

Rajat

@Rajat "Timelessness means worldlessness" Please explain. I don't see any reason why that should be true.

Dear KR,

What is the world ? The world is a sequence of phenomena conceived of by us as a causally related chain of events on an evolving space-like hyper-surface in a forward temporal direction, and therefore, without time no world (as a temporal process) can be conceived to exist.

Probably you are thinking in terms of a static universe having only space and things in it, with no movement or change in any manner whatsoever occurring anywhere. In this case there would be only an uninteresting conceptual existence without any events.

The fact is that we are already born into a world having time and anything that we take away from its integral wholeness of structure and function will surely put our own position in jeopardy, and thus throw the question itself into an abyss of meaninglessness.

The only experience of timelessness that human beings have is an unconscious one in deep sleep, which of course occurs in time again, although the sleeper is unconscious of any time or space or anything at all existing during that phase.

Regards,

Rajat

@Rajat You should read this http://toebi.com/documents/book.pdf (Part of my future book) there I have explained what time really is. Can you see my point of view about time realistic alternative?

Dear Kimmo,

Good luck for the upcoming book containing new ideas.

But time is fundamental to our internal structure and to the structure of the universe and one can surely play around like a child with the idea that it emerges from interactions etc. Any equation that has time on the left and interactions or whatever on the right can surely be inverted, to have the interactions on the left generated by time on the right. Cause and effect are related like that, unless you have a time order in the beginning.

Everything including your TOEI are born in time, they will exist in time and finally they will be consumed by time. This is not philosophy, but the hard reality of all phenomena in this world of ours. Thus I can only wish you all the best and leave the rest to time as it takes good care of everything.

Regards

Rajat

@Rajat Thank you.

Well, obviously we have different views on time, that's quite alright. Actually, it's very fruitful to have a different opinions. You can build up your world where time is fundamental, but at the same time, I can build up my world where time is not fundamental, marvellous!

How much time did it take for this entire discussion so far? Is there any relationship among the various arguments and counter arguments made so far that can be based on a 'time' sequence that follows the cause and effect principle? In case there in none, why do we eagerly wait for the next argument? Why is that any person who views all these arguments after two months from now for the first time will have them all together?

@Sahijpal And still, time is not fundamental. It's calculated based on atomic events, that's all.

The sequencing of events, following the cause and effect principle, demonstrate the inevitable presence of time. It does not matter whether anybody wants to really quantify the measurement of time by a clock. I elaborately mentioned earlier that we (including our perceptions) evolved during the last two million years, whereas, the universe has been evolving for the last 13.8 billion years. It is the time that puts all the events in a sequence followiing the cause and effect principle. As an example, ask a child to take birth before his grand father. Since this is not possible due to the cause and effect principle. Time beomes inevitably fundamental as it basically defines the principle. Within the framework of Physics there is no way of understanding the cause and effect principle in case you ignore time as a fundamental concept.

@Sahijpal I disagree with you. The cause and effect doesn't need time per se. If we study spinning particles where do you need time? Spinning phenomenon generates interactions between other spinning particles. Where do we need time? System of spinning particles enter a scene and exerts a force to a bystanding particles, cause and effect and no time needed.

If we define the magnitude for interaction strength then we need time. But that time is purely man made concept and defined with atomic events. I understand what you are saying but I claim that we can do better!

Time is a name we have given to our perception of the sequence of events. If we consider the Big Bang as the very first event that was the cause of consequent events we can see that events did happen and do happen in spite of existence or nonexistence of any living creature to perceive them. This was not and is not the time that caused and causes events to happen. Some events are cause of other events and some other events just coincide with other events. Time is just a conceptional mean for us to realize the sequence of events. This is the sequence of events that is real and time as perception of this sequence is virtual. It is virtual because it is out of our reach. We can not repeat or reproduce a previously happened event at the same time at which that previous event happened. It will inevitably, disregarding science fictions, happen after the that previous event. Or, when we say one year from now, we actually mean the next time Earth passes the same point it is passing now relative to Sun. In other words we can not go back and forth in time. Our time measuring devices actually compare a set of events with a reference set of events by which we can indicate which event coincide with which reference event. In fact, we are using sequence of events to define time.

The spin argument: The particle spin, or for that matter the particle spin interaction is a purely quantum concept. Any attempt to visualize spin as a 'classical' entity will eventually result in a conceptualize failure. The hyper fine transition in neutral hydrogen atom, responsible for 21 cm wavelength photon in radio region, would occur over a timescale of ~ 10 million years in the absence of collision induced interaction with another hydrogen atom (reduces to ~ 100 years due to collision). This interaction is brought about by the interaction of the magnetic moments of proton and electron spins. This is a purely quantum effect with no classical analogy. The time inevitably comes in this transition. It is by no way any man defined perception. Of course, we can define the time span with different scales.

The cause and effect principle: This principle is exclusively due to the fundamental nature of time that puts sequence of events in a correlated manner. Why is there no coincidence of the birth of several generations of a family at a single time? Because the biology will not allow this. The biological events happen over time. It is merely not a perception of time. Even a single cell needs time to grow and multiply. We don't even need particle spin argument in this classical and simple problem.

Final comments: I have been referring to Statistical Mechanics and thermodynamics in my earlier replies to this query. There are all sort of concepts like time correlation functions, ensemble theories, etc. There are theoretical formulations regarding the tendencies of the systems that are in un-equilibrium state to reach a thermodynamical equilibrium over a timespan. Within the framework of Physics all these concepts are inevitably dependent on time.

@Sahijpal Well, in my theory (ToEbi) particles do spin in classical sense, and with this hypothesis, everything and I mean everything fit nicely together. Relativity emerges, different force interactions emerge, all current anomalies get their answer and so on. QM spin concept is just half way there.

All that without fundamental time. I know it's kind of mind bender, but give it honest chance and think about it.

@Rassouli Time travel is actually possible (in sci-fi sense), but only to a future. This is achieved either with very high speed or under influence of great "gravitating" object.