Rodney Bartlett,

I do not think that Einstein suggests a notion of curvature of space or time or spacetime in such a manner that the future of anything with respect to itself (or parts of it that have been at any other past conglomerations) would somehow be contactable in the present or would somehow have been contacted in its past.

However pefectly the curvature is mathematized, as in the case of the asymptotic nullity in a black hole, that does not mean that the mathematical possibility of the future entering its past proper (i.e., the present and the past with respect to the matter-energy within the existent, of which we discuss the time) exists. If anyone holds so, it is his turn to demonstrate it. Not merely mathematically but also physically. In philosophy there are some who think that the future can affect the present and the past. Mostly this is via their blind acceptance of the non-causality interpretations of QM. There are others who approach the matter via counterfactual multiverse ontology. But I believe these are not productive of any durably tenable cosmology.

There can be physicists guaranteeing mathematically that time does not exist. Equally well, space too does not exist. Space and time need not exist. But our measurements and the mental processes that result in measurements of some or other type need to produce these two (space, time) as the cognitive / epistemic conditions that represent the Extended and Changing aspects of the physical (and physically biological) processes that we are engaged with. Hence, Extension and Change are the physical-ontological counterparts of space and time. These too need not exist. But they are the universal qualities of any existent, I believe.

Now, will the change in any physically existent process (or of course of any part thereof) turn around and take the shape of the effect part informing the causal part?

As you may see in my RG, I have dealt with the foundations of this in many preprints and discussion questions. Hence, I do not elaborate on it here. Nor is it possible in a short space like this.

Thanks.

Raphael

I agree that Einstein didn't suggest communication between periods of time is a consequence of curved spacetime. I'm sure he wouldn't be opposed to the possibility though. After all, the Unified Field Theory he worked on for about 30 years had the aim of uniting everything in the universe (including different times).

I think space has to exist if Relativity is right about gravity being the curvature of space (we all know gravity exists). Maybe the virtual particles currently theorised to fill space are the things that don't exist. And the model of space and time being inseparable says there must be a thing called time if there's a thing called space (which would be filled with real particles called gravitons and photons). (Those particles would share elements of their composition, thus being interactive electromagnetically and topologically).

Einstein's statement about time being "a stubbornly persistent illusion" doesn't simply mean it's an illusion that doesn't exist. It can mean our linear concept of time is the illusion, with "stubbornly persistent" referring to the inevitability of temporal interactions.

Thanks. Now, the problem is when the concept of existence is made the same with respect to (1) space and time and (2) physically existent things / processes. Do you think that (or, do you think that Einstein has held that) space, time, and spacetime are existents like physical beings? If this were to be so, then we can say that not only Raphael exists but also the idea of Raphael...!

Even contemporary Platonism about mathematical notions or objects does not mean that the existence of mathematical objects is the same as that of physical beings.

Now about Einstein's insistence that spacetime curves. I believe that what he and all of GTR should mean by it is that the mathematical expressions show curvature of the spatiotemporally measuremental texture of matter-energy configurations and energy configurations.

If this were not the case, then it would have been enough to say that gravitation is just a spacetime curvature, and a separate gravitation does not exist! Similarly, one could claim that matter, energy, and matter-energy do not exist, but instead, that only spacetime exists, because that would suffice for mathematical work in physics!

I hope you get the point. Kindly feel free to respond. Please note: I am not making haughty assertions here. Each time I write a sentence, it is not good to write that "I think that ...". Please be sure, I am humble enough to have a good, human, and amicable discussion. Please excuse me if my assertive sentences above or elsewhere seemed presumptuous....!

Dear Rodney,

Let's embark on a thought experiment, one I'd like to term the "Echo Before Speaking." This concept serves as a compelling illustration of retrocausality. Picture yourself standing within the confines of a vast canyon. Now, imagine the perplexity you'd feel if you were to hear the echo of your voice reverberating back to you before you've even uttered a word. Such a scenario defies our intuitive understanding, doesn't it? In the realm of our daily experiences, the cause invariably precedes the effect. However, if we entertain the notion of a universe where time doesn't adhere to a strict linearity, where the past, present, and future coexist and intertwine, then such an occurrence might not be as far-fetched. The phenomenon of solitons serves as a testament to this idea.

To truly grasp the essence of this "pre-echo," it would necessitate us to stretch our perceptual boundaries beyond the immediate present. Drawing a parallel to your mention of Paul McCartney's creation of "Yesterday," it's as though a future McCartney reached back through the corridors of time to plant the melody and lyrics into the mind of his younger self.

This brings to mind the cinematic narrative of "Arrival," where the extraterrestrial beings possess a perception of time that starkly contrasts with human understanding. Their circular language, devoid of a start or end, mirrors their cyclical perception of events, challenging our linear perspective. Perhaps the key to unraveling such mysteries lies in broadening our perceptual horizons, much like the protagonist in the film.

The human experience is profoundly shaped by our perceptual systems. Our senses provide a window to the world, filtering and interpreting the vast array of stimuli that surround us. Yet, these systems are not infallible; they have evolved to prioritize certain types of information over others, based on what has historically been most relevant for our survival. As a result, there are countless phenomena that exist beyond our immediate perception, either because they fall outside the range of our sensory capabilities or because our brains do not deem them significant enough to process.

Ludwig Wittgenstein's assertion that "The limits of my language mean the limits of my world" underscores the idea that our understanding of reality is intrinsically tied to our ability to describe and conceptualize it. Language is not just a tool for communication; it shapes thought and defines what is conceivable. If we lack the words or concepts to describe a phenomenon, it becomes challenging to think about or even recognize its existence.

Building on this, Einstein's revolutionary ideas about the nature of time further challenge our perceptions. He proposed that time, rather than being an absolute, unchanging backdrop against which events unfold, is relative and can vary depending on one's state of motion. This concept of time's relativity shatters the intuitive, linear understanding of past, present, and future that our language and everyday experiences seem to support. Instead, it suggests that our perception of time's flow might be just another illusion, a construct of our minds and languages. In essence, both Wittgenstein and Einstein highlight the potential pitfalls of trusting our perceptions and the languages that describe them too implicitly. While they offer invaluable insights into the world around us, they also come with limitations. Recognizing these boundaries is crucial, for it reminds us of the vast unknowns that lie beyond our current understanding and challenges us to continually seek broader perspectives and deeper insights.

Warm regards,

Alessandro

Raphael,

Everybody probably sounds presumptuous at times without meaning to. We try so hard to express our ideas clearly that we seem to arrogantly state ideas as facts. But don't worry - you don't seem presumptuous to me.

When he was a young man inventing Relativity, Einstein relied on his intuition a lot. He appears to have used maths mainly as a means of persuading mathematicians that his ideas were correct. It's possible that he anticipated the holographic principle of the universe in which the 3rd dimension results from information in a 2nd dimension. Then he would only have used the idea of 4-dimensional spacetime to help mathematicians understand Relativity.

This mathematical existence of spacetime wouldn't perfectly represent its physical existence as made clear by Einstein's publication in 1919 of an article suggesting gravity plays a role in the composition of elementary particles. This might mean (1) gravity and electromagnetism can undergo a particular interaction to form particles with mass, and (2) space, while filled with gravitons and photons, is nothing but the absence of the mass-generating interaction.

There can be no curvature of something that has no existence itself. The phrase "curvature of space" would technically mean "gravitons and photons filling space follow curved paths".

Hi Alessandro,

After reading the start of your message, I imagined what I'd actually feel if I heard my echo before making a sound. I'm rather familiar with coexistence of all time periods in theory but not so much in practice (after all, I can't take a trip in a time machine every day). If I had an echo before speaking, I'd turn into 5+ feet of total perplexity!!

It might help me broaden my perceptions if I could grow up again, only immersed in an "Arrival"-like civilization this time. But like Wittgenstein's and Einstein's ideas, this would also have limitations. It'd be incredibly difficult for Arrival's aliens to truly understand the exclusively linear time of Earthlings.

The aliens have things to learn. The Earth people have things to learn. No matter which planet we live on, no matter which century we live in, we all have things to learn. And there will probably be more to learn even if we're alive literally forever. That's very strange but it sure beats getting bored.

Rodney Bartlett, Alessandro Rizzo,

How to show that time can negatively curve on itself? By time I mean measured, measurable, and thus epistemic time. Now, if we can agree that time is the measure of Change, then we need to show that Change curves in on itself and returns at times (or always?) from the future to the present and the past or ordinary reckoning.

Surely, time (as I characterized above) is not absolutely linear. But not absolutely linear does not automatically mean that it is negatively curved. How can holography show that time is negatively curving? Any real experiments made? Or, only a suggestion or hypothesis? Holography is a theory, and not a direct representative of what happens in nature, unless this is proved!

In my opinion, physics, philosophy of physics in particular, and philosophy in general have argued a lot FOR CENTURIES about the non-linearity of time as measurement of physical processes in conglomerations of any size. If we have only a universe with a finite content of matter-energy, then it is possible but not necessarily true to speak of phases (expansion, contraction) of this universe. Let us grant that the phases would occur. Even here, regarding the contraction phase can we affirm that time is returning with a negative curvature?

If these evolutionary phases were not true of our universe, then is there any reason to claim that measuremental time returns in any holographic region of the universe?

Further, if the universe is a multiverse of infinite matter-energy content, it would naturally possess an infinite number of minor universes like our big bang universe of finite content. In such a scenario, what to say about the proper measuremental time of each of these? Will they all holographically be united and then obtain negative curvatures? I wonder!

Dear Raphael,

Your questions touch upon some of the most intricate aspects of theoretical physics, especially when it comes to the nature of time, spacetime curvature, and particle physics. Let's delve deeper with a refined approach:

1. Negative Curvature, Möbius Geometry, Particle Spin, and Time: Negative curvature is emblematic of hyperbolic geometry, often visualized as a saddle shape. This contrasts with the positive curvature of a sphere. The Möbius strip, with its unique topological properties, challenges our standard notions of "inside" and "outside." In such a topology, time can exhibit both negative and positive curvature, suggesting a more intricate and interconnected relationship between events than our classical understanding allows. When we consider particle physics, the spin of elementary particles might be linked to this geometry of spacetime, hinting at the non-trivial topological properties of certain quantum fields.

2. Curvature and Frames of Reference: As you've rightly pointed out, curvature is relative to our frame of reference. A straight line on paper might seem linear, but if that paper is on Earth, it's technically on a curved plane. Our perception of curvature is deeply tied to our observational scale.

3. Quantum Mechanics, Time, and Clocks: Quantum mechanics challenges our classical views of time and space. Clocks, which measure time, fundamentally rely on cyclical processes, like the oscillation of a quartz crystal. This cyclicity can be likened to a frequency of events on a statistical scale. At the quantum level, the linearity of time becomes more ambiguous, and spacetime itself takes on a more probabilistic nature.

4. Solitons: Solitons, as self-sustaining wave phenomena, arise as solutions to certain nonlinear partial differential equations. Their existence isn't solely tied to media with negative curvature. Instead, their manifestation is more about the nature of the interactions within a medium, regardless of its curvature.

5. Holography and Time Curvature: The holographic principle posits that all the information in a volume of space can be represented on its boundary. This concept, while revolutionary, especially in the context of black hole physics, doesn't directly suggest a negative curvature of time. It provides a fresh framework for understanding spacetime, but concrete evidence, especially regarding time's potential negative curvature, remains to be found.

Thus, our understanding of time, spacetime curvature, and particle interactions is continually evolving. While theoretical constructs offer tantalizing possibilities, empirical evidence remains the ultimate arbiter of truth. Many of these ideas are still within the realm of theoretical physics, awaiting experimental validation.

So the nature of time and its potential non-linearity is a topic that has fascinated physicists for decades. Some of the key areas of research and phenomena that suggest a possible retrocausal nature of time are:

1. Double Slit Experiment and Retrocausality: One of the most renowned experiments in quantum physics is the double slit experiment. In certain interpretations, the observed interference pattern suggests that particles "choose" a path based on future measurements. This has led some physicists to speculate on the possibility of retrocausality, where future outcomes influence past events.

2. Quantum Entanglement: Entanglement is a phenomenon where particles become so correlated that the state of one particle instantly determines the state of another, regardless of the distance separating them. This "spooky action at a distance," as Einstein once termed it, has led some to suggest that there might be a form of retrocausal communication, although this interpretation remains contentious.

3. Wheeler and Feynman's Theories: Physicist John Wheeler and his student Richard Feynman proposed a theory wherein antimatter particles are actually particles of matter traveling backward in time. While this idea isn't widely accepted, it serves as an example of how retrocausality concepts have been entertained in physics.

4. Einstein's Theory of Relativity: Einstein's general relativity allows for mathematical solutions, such as wormholes or "Einstein-Rosen bridges," which could, in theory, enable time travel. However, the stability of these structures and their practical feasibility remain subjects of debate.

5. Delayed Choice Experiments: These experiments, which are variations of the double slit experiment, demonstrate that decisions made at a future point can influence measurements taken at an earlier time. While they don't directly prove retrocausality, they raise fundamental questions about the nature of time in quantum mechanics.

Anyway I emphasize dear Raphael that while these phenomena and theories hint at the possibility of retrocausal effects or a non-linear nature of time, there isn't a consensus within the scientific community regarding these interpretations. The nature of time and its potential retrocausality remain among the deepest mysteries in physics.

Warm regards,

Alessandro

Alessandro Rizzo

I think that more than physicists it is some philosophers who moot retrocausality and negative curvature of time. When we say that these are mysteries, I hope that no reader will conclude that these are absolute mysteries. We ARE able to know something generally about these things. Call to mind believers naming God as a mystery, and then they term anything not explained in plain words as mystery kept away from human minds.

So long as space and time are measuremental, they are epistemic. But they have a fundamentum. The fundamentum is existent physical things. From the experience of existent physical processes here, can we not conclude for sure at least some general characteristics of all physical existents? These are Extension and Change. Extension is not absolute stability or changelessness. It is the nature of having parts. Change is the ability of extended things to cause impact on others and thus on themselves. It is a two-way action, but IN AN IMPACT-ACTION DIRECTED AT THE OUTSIDE, the former is the first and then comes the specific change within as caused by the impact on others. And vice versa. But the former-later aspect is irreducible. Hence, it is defined by Change, and not by time. Time is the epistemic aspect of Change. Similarly, space is the epistemic aspect of Extension. Extension and Change are in physical processes, not in our concepts taken as abstract entities.

Hence, in my opinion, it is one of the most unfortunate follies of humanity to go on claiming that spacetime curves, instead of admitting that Extension-Change is finitely active in physical processes! If the physicist believes that physical processes do not have infinite Extension and Change, then they should also accept that Extension-Change-curving is finite.

In the light of these arguments, how would you view 1-5 in your intervention?

Dear Raphael,

Thank you for sharing your thoughts on the nature of space and time. Your ideas about Extension and Change as the foundations of space and time are very interesting!

Well let me address the topics you brought up:

1. Double Slit Experiment: This experiment questions our usual understanding of cause and effect. However, it doesn't necessarily mean that events can be influenced by future actions. We can explain the results using the standard rules of quantum mechanics without needing to think about effects going backward in time.

2. Quantum Entanglement: This is a fundamental part of quantum mechanics. Even though it might seem strange, it doesn't mean that information is traveling back in time. The connections we see between entangled particles can be explained without this idea.

3. Wheeler and Feynman's Ideas: The thought of particles moving backward in time is interesting, but it's more of a mathematical idea than a real description of how the world works.

4. Einstein's Relativity: Relativity does suggest the possibility of things like wormholes. However, we haven't observed these, and even if they do exist, we don't know what they would mean for our understanding of time.

5. Delayed Choice Experiments: These experiments make us question our usual ideas about cause and effect. But, like the double slit experiment, they can be explained using quantum mechanics without needing to think about retrocausality.

Your idea that Extension and Change are the real basis of space and time is thought-provoking. If we think of space and time as coming from the interactions of physical things, it gives us a new way to think about topics like the curvature of space or the possibility of retrocausality. But, we also see real effects from space and time, like how gravity bends light or how time seems to slow down for fast-moving objects. This suggests that space and time are more than just ideas; they have their own reality.

So, while our theories give us a lot of insight into the universe, they also have their limits. We should always be ready to question and update them based on new evidence and ideas.

Warm regards,

Alessandro