Dear @Marcel, I think, for the early beginning of this thread, the paper The Definition of Time is an appropriate one. I will discuss later about the issue! @Demetris paper is also attached!

Article The Definition of Time

Article A simple definition of Time

Dear @Marcel, I think, for the early beginning of this thread, the paper The Definition of Time is an appropriate one. I will discuss later about the issue! @Demetris paper is also attached!

Article The Definition of Time

Article A simple definition of Time

Why complicating this discussion with 'complicated' human-invented mathematics (Astrophysics etc....)? The fact is that 'time' is measured/defined with 'change' of something, like the rhythm of an atomic clock.... I do not need mathematics to provide arguments for this statement... If you do not agree, please give me some simple convincing arguments why we need 'time' to understand from a theoretical point of view the true nature of nature?

There is a difference between the intellectual need to define what people call 'Time' and 'Time' as a fundamental part of nature. I only perceive 'Change' expressed in evolving matter, movement..., not time, so why scientists should be interested in phenomena like time that cannot be seen?

Dear All,

I think prior to discuss this question we should read the two papers Ljubomir cited. Regarding the very easily understandable and nice article of Demetris, I like it really but the part on time and economy seems to be a not imperfect example because economy is a totally artificial human creation which has nothing to do with natural laws except some a bit lame analogues.

Dear Marcel,

Oversimplification does not always simplify things.

Several points for discussion, accepting there is overlap with the contents of the published papers dealing with time:

- Time is only visible/measurable through physical change and therefore theoretically not necessary when you have already access to change.

A time measure is not more than one of the many ways to measure change.

Physics ignoring time will compare/analyze systems that change differently. The 'change measure' called 'time' will be a reference system to which other systems of change are compared.

Examples:

- Person X requires 'x degrees sun movement' or 'x vibrations of an atomic clock z' to conduct a task.

- Person X requires 'x degrees sun movement' or 'x vibrations of an atomic clock z' to walk one mile. Person Y requires 'y degrees of sun movement' or 'y pulses of a distant pulsar' to run one mile.

Is time not more than a human invention/tool to standardize methods that measure change?

'Time' is defined as a unidirectional flux going from the past to the future. Perhaps this could also be claimed for 'Change', accepting that each new event is unique in physical expression, even in what people call 'rhythms'?

Dear Orkid,

Does nature and it's processes take all these human thoughts into account? What is the significance of a human lifetime in an 'infinite' universe?

In an ever expanding or shrinking universe, every event is unique in physical expression, either caused by change in matter or change in position....

Example:

An atomic clock will permanently change position because objects/matter moves in space, which implies that every tiny aspect of a rhythm used to 'measure time' will change.

All these arguments are based on what I read, not what I perceive.

Dear Orkid,

how are your last remarks linked with the former remarks and the definition of time? Perhaps you want to say that 'entropy' is physically never repeatable complicating the definition of what people call time?

Is time only needed in a static world, e.g. a phenomenon that does not change in physical expression? Is there any evidence for a truly static world?

A remark placed in a 'Darwinian evolutionary perspective' addressed to the smartest people on Earth: 

Are all these philosophical discussions about 'Time' caused by the fact that the human brain results from Darwinian selection (natural selection, sexual selection)? For instance, humans do not need to know all the details in nature to survive and reproduce, perhaps implying that the human brain has not been selected to understand the functioning of the (whole) universe.

Dear Orkid,

I cannot do more than what I explained before. I just used personal mental states to make interpretations of the functioning of the world as others did before.

Thanks for the interactions

Dear Francesca,

Just to stimulate more discussion:

Some consider the products of Intellect also products of Nature, for instance when Intellect is brain structure dependent and brain structures evolved via natural/sexual selection processes. The human-defined distinction between what you call 'Natural' versus 'Artificial' might also be either 'Artificial' or 'Natural', simply depending on the framework of analysis or perception....

A human-produced clock could in this context either be defined as Natural or Artificial.

time is a change all around

"Time is just an illusion. Einstein told us that."

"What quantum physicists and Einstein tell us is that everything is happening simultaneously."

"There is no time for the Universe and there is no size for the Universe."

but i don't agree with the above concept

i my understanding there is a size of universe and time does exist in form of change and measure of relative nature of objects 

I presume that different living beings perceive 'Change' or human-invented time as a proxy of 'Change' differently, even if they are in the same place having the same speed.   

Dear Marcel,

I don´t know if You aim to the different time feeling eg of a dayfly. These animals must have a total different experience of time.

Dear Hanno,

yes, I also had a dayfly in mind.

Theory in Physics, including the definition of Time is mainly based on mental experiments conducted by the human brain (cf. A. Einstein and the development of general relativity theory).

However, evolutionary biologists might claim that the human brain and its mental performance results from Darwinian selection (natural selection, sexual selection) where human brains do not need to capture/perceive all the details in nature to survive and reproduce.

If we would combine evolutionary biology with brain perception abilities and mental experiments to develop Theory, such as those related to the definition of Time and the perception of Change, what are the potential implications of theory development in Physics across living beings? For instance, would ants, humans and undiscovered extraterrestrial organisms all be able to propose exactly the same theory in Physics, given that different organisms are exposed to different kinds of perception constraints influencing how mental experiments are designed and conducted to develop theory?

Is the universe and its components perceived differently by organisms differing in perception constraints? Are perception constraints minimized in humans so that a nice unbiased picture can be obtained about the functioning of the universe, including aspects dealing with Change and Time used as a proxy or special case of Change?

Psychology/Ethology: Ask people to estimate the length of an event without having access to a watch. Estimates will most probably differ between individuals because of X reasons.

Non-human living beings on Earth live without 'artificial' time-measure devices, and therefore have to rely on aspects related to environmental change (e.g. seasonality) to make decisions.  When 100 people without a watch are asked to walk 10 km, and are then asked to estimate the duration of the walk, we will probably have more than >90 different answers. What is the 'adaptive value' of people without a watch providing different 'time estimates' for the duration of a walk? Does it imply that the human-invented time concept is unimportant in nature?

Human-invented time is a tool to synchronize and manage activity, which has nothing to do with the physical existence of (dynamics of) time as discussed in Theoretical Physics.

The actions of Pineal Glands involve biorhythms that reflect biological CHANGE, not TIME? 

Biology-based synchronization between two phenomena/events involves matches of change-dependent rhythms (fluctuations in change), not time-dependent rhythms? 

In terms of TIME since your August 10th response, it has passed 4 months! Long TIME dear @Marcel! Let's act!

Long TIME or much CHANGE?

Cheers

There are a huge number of theoretical definitions of time. I would like to present you an implemented / empirical one, mine! To define time we need to measure exactly the changes of a simple entity which have to be independent of the things we want to observe. The choice of this entity depends on the desired validity and reliability precision. During the observation other things (including the things we observe) can change or not. Time is also not a universal thing but a specific instrument from a specific perspective. Even if this instrument is well established (like the length of a year or a date, the use of an atomic time).

Accepting that everything changes (perceived or not perceived by the human observers), human-defined time has to take relative differences in change into account?

These relative differences in change will be scale of analysis-dependent, which also implies that the human-defined time cannot have universal value?

Well, dear Marcel, we have first to differentiate between the principle and the measure. The human define time principle is universal for human. (Just few tribes have no word for time or notion of past and future). Not the measure of it.

If you look outside the human-defined time, you have still first the anthropocentrism issue. Second you still have the reference point issue. Time is always specific. Even if you use the expansion of the universe as reference point/process.

Thank you!