:smile: G'day!

that time moves obliquely according to a functional operator and we experience only a projection of it in our spacetime geometry. — jgill

I'm not sure if you are serious here... :chin:

We all know it. Time is unidirectional — EugeneW

Well, I don't. I don't know that time is unidirectional. That is, I don't know that time is moving in one direction. In fact, I don't think that time is moving at all. The wind moves in one direction. The water in a river moves in one direction. The earth moves around the sun in one direction. All these things have one thing in common: they are physical. Time is not. Thus it cannot move. It is itself movement. In the sense that it represents movement and change.

The unidirectionality of time is an illusion. It is we who have assigned this quality time. After of course having created the concept of time itself. Time itself does not exist. Not more than length, width and height exist. They are all dimensions. We have create them for purposes of measurement, comparison and reference. So we call the Earth's rotation around its axis a "day" and its orbit around the Sun a "year". It is these movements that are unidirectional. Not time.

***

As for the reason why all these movements are unidirectional, it can be found in Laws of Physics..

Well, not me. I don't know that time is unidirectional. That is, I don't know that time is moving in one direction.

:up: :100:

Sometimes linguistic philosophers or people in linguistics like the idea that languages where verbs have no temporal inflection are used by people who have no awareness of time.
[...] Greek philosophers themselves did not notice the aspect system in their own language but began the tradition of thinking exclusively in terms of past, present, and future. Yet in the subjunctive and imperative moods, Greek verbs are only inflected for aspect. Thus, Aristotle's analysis of "future contingency" in On Interpretation would have been stronger and made better sense as "imperfect contingency."
If you are interested, I recommend you this essay: Past, Present, and Future, A Philosophical Essay.

I dont think time is flowing. The hands of the clock move though. So motion is time. Periodic motion is the clock, irreversible motion what it measures and quantifies. — Hillary

I don't think time is flowing either, and it is not motion. Motion is not time. Motion is just motion.

I don't think time is flowing either, and it is not motion. Motion is not time. Motion is just motion. — Corvus

I think periodic motion, be it the Earth strolling around the Sun, or a pendulum swinging, or an atom oscillating, can be considered as the motion in clocks. There are no truly periodic motions in nature, so it's a made up thing. We mentally compare the progress of processes with an ideal clock, and it turns out that the speed of this process, and thus the speed of the irreversible processes it measures the time of, has no inherent quality. Only when compared with other clocks, the clocks can be said to go faster or slower. The periodic motion with which we measure time passed is not a quality inherent to the process. But the number of times a, say, pendulum has swung next to a process says something about the process. The funny thing is that before thermodynamic time was kicked of, there were processes going on to make the kick possible. These processes did not have an asymmetry in time. They can be seen as fluctuating in time. The pre-inflationary state can be seen as a perfect pendulum. Not going backwards in time, nor forwards, as thermodynamic time still had to emerge. What kind of motion was that? Think about it. Did you have a good dinner at the office, btw?

Well, I don't. I don't know that time is unidirectional — Alkis Piskas

Don't you think time goes forward only? What direction in time goes a clock or a pendulum? If it's an ideal clock you couldn't tell. It could be going forwards or backwards. All processes seem to be directed towards the future, even when you consider the universe a block. Why are processes on this rigid block structure move from small to big t? Why not the other way round?

The pre-inflationary state can be seen as a perfect pendulum. Not going backwards in time, nor forwards, as thermodynamic time still had to emerge. What kind of motion was that? — Hillary

You don’t consider that periodic motion?

The unidirectionality of time is an illusion. It is we who have assigned this quality time. After of course having created the concept of time itself. Time itself does not exist. — Alkis Piskas

Not according to Ilya Prigogine or Lee Smolen. For them time is fundamentally unidirectional. We didnt create time, although we create various theories about time. The things we are attempting to measure are in themselves incoherent without the prior being of time.

Yes, but the motion was periodic in time too. Virtual particles can be represented, if not coupled to real particles yet, as a closed propagator line in space time, or energy momentum diagram. A vacuum bubble is just a single particle rotating in spacetime (so not a particle-antiparticle pair).

Thanks for both your :up: and your reading reference.

BTW, in your quote of mine you have left out the most important part, namely, that time does not move at all. My whole point was that. (Just "I don't know that time is moving in one direction" can well mean that I think time is moving in two directions! :grin:)

Yes, but the motion was periodic in time too. Virtual particles can be represented, if not coupled to real particles yet, as a closed propagator line in space time, or energy momentum diagram. A vacuum bubble is just a single particle rotating in spacetime (so not a particle-antiparticle pair). — Hillary

Linking somewhere deep within the presuppositions
informing this physics vocabulary is a philosophy of time, but I’m not familiar enough with the physics jargon to get at it.

You think time is a stationary fixed axis, with clocks on it showing different times? If so, then what is moving?

Well, I don't. I don't know that time is unidirectional.
— Alkis Piskas
Don't you think time goes forward only? — Hillary

I didn't say only that, did I? I also said that time does not move at all. My whole point was that!

Not according to Ilya Prigogine or Lee Smolen. For them time is fundamentally unidirectional.. — Joshs

I don't know about these persons. And good for them if they believe that "time is fundamentally unidirectional". (BTW, does "fundamentally" mean that it can also be otherwise?)

We didnt create time, although we create various theories about time. — Joshs

I didn't say that we have created time. That would be totally ridiculous. I talked about the concept of time. In fact, in bold letters. I couldn't stress it more ...

The things we are attempting to measure are in themselves incoherent without the prior being of time. — Joshs

We are not "attempting" to measure. We are measuring them. Time is just a dimension. As is length. They do not actually exst.

I didn't say only that, did I? I also said that time does not move at all. My whole point was that! — Alkis Piskas

Yes, that's clear. There are only irreversible particle processes. Don't they move in a stationary time?

Isn't a clock moving? Isn't a pendulum going to and fro periodically? Can't you move the pendulum? Doesn't the pendulum have double motion even?

I didn't say that we have created time. That would be totally ridiculous. I talked about the concept of time. In fact, in bold letters. I couldn't stress it more ...

The things we are attempting to measure are in themselves incoherent without the prior being of time.
— Joshs
We are not "attempting" to measure. We are measuring them. Time is just a dimension. As is length. They do not actually exst. — Alkis Piskas

Measurement presupposes a concept of measurement, so there is an ‘attempt’ prior to the measurement. Time understood according to certain long-standing assumptions shared by philosophy and science is just a dimension. But to philosophers like Bergson and the phenomenologists it is the structure of reality itself. Dimensions are convenient abstractions that are useful
to us, but original time is not an abstraction, an invention, an idealization. If time as dimension is a human invention, what features of the world can you point to that are not human inventions?

But to philosophers like Bergson and the phenomenologists it is the structure of reality itself. — Joshs

But how does that structure look like? What is it that is measured by the clock? If the periodic clock process has completed x periods, then what corresponds this x to? And what if time proceeds in steps, then how does the process know when a static scene has to progress to the next? How does it know it takes a Planck time?

I'm not sure if you are serious here... :chin: — Hillary

I can physics babble as well as anyone here if I put my mind to it. :wink:

Isn't a clock moving? Isn't a pendulum going to and fro periodically? Can't you move the pendulum? Doesn't the pendulum have double motion even?

These objects which "represent" time are related to the move of sun, not to the motion of time. This is why the first clock ever created was in Ancient Egypt and this specific clock was connected to the variation from the sunlight
The "heliacal rising" of Sirius means the morning (and the Egyptian day began at dawn) on which the star Sirius can first be seen in the eastern sky right before sunrise. This was to the Egyptians the astronomical beginning of the year, though the actual heliacal rising moved through the Egyptian calendar, since the Egyptian calendar year was 365 days long with no leap day.

There are only irreversible particle processes. Don't they move in a stationary time? — Hillary

"Stationary" means "not moving". The possibility of moving is implied. Water can be stationary. A statue is stationary. Inflation can be stationary. They can all move but they don't.
Time cannot be stationary because it not something that can actually move. Only figuratively, e.g. "times flies", "time passes by", "time has topped" ...

What is it that is measured by the clock? If the periodic clock process has completed x periods, then what corresponds this x to? And what if time proceeds in steps, then how does the process know when a static scene has to progress to the next? How does it know it takes a Planck time? — Hillary

Husserl, Heidegger, Derrida, Deleuze and Bergson have shown in different ways that a quantifiable, mathematizable nature presupposes the kind of time which consists of self-presences transitioning from future to present to past in sequential movement (existing ‘in' time). What does it imply to make a time measurement based on clock time, to state that it takes certain amount of time for some process to unfold?

A clock-time calculation counts identical instances of a meaning whose sense is kept fixed during the counting . To count is to count continuously changing instances OF something that holds itself as self-identical through a duration or extension.

The above writers agree that there are no self-identical objects, but rather qualitatively changing events, and clock time results from an idealization in which we posit enduring objects that are either at rest or in motion. The seemingly simple conpet of movement is a complex psychological construction.

I can physics babble as well as anyone here if I put my mind to it. — jgill

Well, I haven't seen much physics babble here. I wished there was. So... mr. Gill... Explain please:

"that time moves obliquely according to a functional operator and we experience only a projection of it in our spacetime geometry."

Time moves obliquely according to a functional operator. What's the functional operator? Is there a motion of time outside of spacetime? Is there a rotation of a vector in a complex plane, underlying spacetime, which, when projected on spacetime, determines real space or time? I can feel what you mean somehow but am not sure of what you mean. You're just fooling around! Like we all are, I guess. Be it the wise Rovelli, the greedy Carroll, or the Witten mathematical ivory tower, or the friendly Smolin, or even AI-ist Piskas....

These objects which "represent" time are related to the move of sun, not to the motion of time. This is why the first clock ever created was in Ancient Egypt and this specific clock was connected to the variation of light from the sun.
The "heliacal rising" of Sirius means the morning (and the Egyptian day began at dawn) on which the star Sirius can first be seen in the eastern sky right before sunrise. This was to the Egyptians the astronomical beginning of the year, though the actual heliacal rising moved through the Egyptian calendar, since the Egyptian calendar year was 365 days long with no leap day. — javi2541997

Interesting! So time was connected to day and night rythm? Aren't there many rythms to compare with,m

Not according to Ilya Prigogine or Lee Smolen. For them time is fundamentally unidirectional..
— Joshs
I don't know about these persons. And good for them if they believe that "time is fundamentally unidirectional". (BTW, does "fundamentally" mean that it can also be otherwise?) — Alkis Piskas

Form Wiki:

“Smolin argues for what he calls a revolutionary view that time is real, in contrast to existing scientific orthodoxy which holds that time is merely a "stubbornly persistent illusion" (Einstein's words).[1] Smolin reasons that physicists have improperly rejected the reality of time because they confuse their mathematical models—which are timeless but deal in abstractions that do not exist—with reality.[1] Smolin hypothesizes instead that the very laws of physics are not fixed, but that they actually evolve over time.”

“In his 1996 book, La Fin des certitudes, written in collaboration with Isabelle Stengers and published in English in 1997 as The End of Certainty: Time, Chaos, and the New Laws of Nature, Ilya Prigogine contends that determinism is no longer a viable scientific belief: "The more we know about our universe, the more difficult it becomes to believe in determinism." This is a major departure from the approach of Newton, Einstein and Schrödinger, all of whom expressed their theories in terms of deterministic equations. According to Prigogine, determinism loses its explanatory power in the face of irreversibility and instability.

Prigogine traces the dispute over determinism back to Darwin, whose attempt to explain individual variability according to evolving populations inspired Ludwig Boltzmann to explain the behavior of gases in terms of populations of particles rather than individual particles.[24] This led to the field of statistical mechanics and the realization that gases undergo irreversible processes. In deterministic physics, all processes are time-reversible, meaning that they can proceed backward as well as forward through time. As Prigogine explains, determinism is fundamentally a denial of the arrow of time. With no arrow of time, there is no longer a privileged moment known as the "present," which follows a determined "past" and precedes an undetermined "future." All of time is simply given, with the future as determined or as undetermined as the past. With irreversibility, the arrow of time is reintroduced to physics. Prigogine notes numerous examples of irreversibility, including diffusion, radioactive decay, solar radiation, weather and the emergence and evolution of life. Like weather systems, organisms are unstable systems existing far from thermodynamic equilibrium. Instability resists standard deterministic explanation. Instead, due to sensitivity to initial conditions, unstable systems can only be explained statistically, that is, in terms of probability.“

Stationary" means "not moving". The possibility of moving is implied. Water can be stationary. A statue is stationary. Inflation can be stationary. They can all move but they don't.
Time cannot be stationary because it not something that can actually move. Only figuratively, e.g. "times flies", "time passes by", "time has topped" ... — Alkis Piskas

What if time is static, without the possibility to move? Just lines with numbers relative to which processes unfold. Can't the unfolding itself be time? And the line with numbers just a construct to catch the process with?

I guess it was compared to day/night rhythm for practical reasons. They did most of the actions during morning and afternoon, then they working day ended up at night. For Ancient Egypt it was so important the role of the Sun to all the characteristics. They even blessed it as a God.
[...] the birth of the sun god Rê, , which is going to be a New Year event.

Husserl, Heidegger, Derrida, Deleuze and Bergson have shown in different ways that a quantifiable, mathematizable nature presupposes the kind of time which consists of self-presences transitioning from future to present to past in sequential movement (existing ‘in' time). — Joshs

So time passing through us from the future to the past. Showing us more and more what's in store for us?

A clock-time calculation counts identical instances of a meaning whose sense is kept fixed during the counting . To count is to count continuously changing instances OF something that holds itself as self-identical through a duration or extension. — Joshs

Yes. Say a calculation of a period of a pendulum. We can look how many times the pendulum has swung back and forth and calculate the time involved. If its a perfect pendulum it's of course the number of periods counted. But why should the processes it counts the passed time of go forward and not backward. Why isn't time pulled through us the other way, the past first and the future following, instead of the future first and the past following?

In deterministic physics, all processes are time-reversible, meaning that they can proceed backward as well as forward through time — Joshs

This is not true. In deterministic physics, not all processes are time-reversible. There are no reversible processes in nature. All processes are irreversible processes. The question is why they are moving towards higher entropy and not to lower entropy.

It could have been such that the universe started in reverse at infinity. But it didn't. — Hillary

No. You don't know that and the concept of infinity ...isn't a starting point.