A growing number of scientists are convinced the future influences the past

We cannot observe in any subset of possible universes where entropy is not present or is working backwards-Ergo those possibilities are wholly out of our direct perception.

That does not mean that causality cannot run in reverse, however, only that we cannot interact with those mechanisms in a way that would preclude our existence or observation.

Sure, but some claims which cannot be tested experimentally or observationally are nonetheless important. For example, the claim “it’s important that scientific hypotheses be tested experimentally or observationally.”

It doesn't defy the direction of entropy. Frankly, I'm not sure why you have that notion? Entropy is a measure of system's state of equilibrium. Moving energy from a concentrated source, and distributing it more equally (across life forms and other complex structures), is following the direction of entropy, as is it makes energy more equalized, in contrast to the former state where energy levels are more unequal between highly concentrated areas (like stars, the Big Bang), and areas with less energy.

At least in France we take as fait accompli that causality is non trivial and that objects are non local at best: either you can consider objects as one despite immense distance between them, or you accept information passed between them in reverse time. Both are hard to swallow.

The regular arrow of time from the human perspective, "leaks" changes into the future. The future is constantly being changed by the past.

You can measure those changes by many ways, the 2nd. law of thermodynamics is everywhere just to make sure you see this happening across everything.

So, probably there are other non-discovered underlying mechanisms in the reality that are already signaling changes from the future "leaking" into the past, changing the past right infront of us, without us noticing it.

A probably omnipresent mechanism for observing the future changing the past, valid in the whole cone of light visible to us, is the probability law.

If you have 10 millions of possible events in a probability, one of them is the exact thing it will happen in the future, hence the information of what happens in the future is right here, existing in the past.

Yeah, you can say how would the nature could use this information without powerful processors predicting branches trillions of times per second on Earth right now?

Well, the brain is a pattern predictor, quite several parts of the brain are firmly attached to the physics of the universe, biochemically but what if the pattern prediction mechanisms in the brain are actually an adaptation of the evolution, just like wings to fly, but with those mechanisms the brain uses probability to "see" information from the future, and here in the "present", it changes the past (from the perspective of the future created originally from the past), if the brain "chooses now" to do something different that what originally created the future it "saw" by analizing patterns, essentially evaluating probabilities.

So the Probability Law would be a kind of Inverted 2nd. Law of Thermodynamics.

It would work perfectly as law of the universe: from the future to the past, the revered time of arrow, one single event created "a" future, but from the regular arrow of time, there would a range of probable future outcomes which you cannot precisely say it has "1" (100%) probability of ocurring, right to exact moment till the future becomes the present.

And it was right there all the time, something obvious infront of everybody in the world, like electricity (which was suspected by many across thousands of years, but just "discovered" recently).

https://en.wikipedia.org/wiki/Law_of_total_probability

It's basically a softer version of Russell's paradox but for cognition and reality.

No. At least as early as Arthur Eddington when Penrose was a twinkle in his dad's eye.

The validity of a coordinate system with the earth stationary at the center is guaranteed by the general principle of relativity. To get the stars to circle around it you would add a radially increasing potential in classical mechanics, or some coordinate shenanigans in GR. These coordinate systems are used in aerospace engineering to get convenient expressions of L1 points, etc.

I know it sounds hard to believe, but if you're willing to bite the bullet that "the center of the universe" has no physical meaning, then earth can't be not the center of the universe any more than it can be.

Or if I’m lucky enough to have the time to watch the moon move slowly, it feels natural to my senses to say it’s moving across the sky. The moon feels like it’s moving around me. But I can stretch my brain and imagine the reality.

Sometimes math arrives first. We have the new maths (or an problem in current math), and that points to some possibility. Because it’s not observable, ignoring our senses is a requirement to develop that in the model and measurements and experiments. Eventually we are able to observe it.

I’m not familiar with history of astronomy. Would it be the case where the observations that lead to heliocentric thought we nuanced and had to build on more obvious perceptions that things aren’t adding up? Was the wobble of Venus part of that?

And you’re right, old models are useful and remain relevant a lot! The model of time moving linearly will likely always be the most useful model for navigating our daily choices (if we have any at all!)

Imagine a ball being thrown up and then falling down, in a parabola. Reversing a video of that still gives you a video of a ball in a normal parabola trajectory.

F = ma

F = m dv/dt

u = -t dv/dt = -dv/du

- F = m dv/du

If you stop there it looks like you're right, but you also must change the definition of velocity to account for the new time.

v = dx/dt = -dx/du

+F = m dx/du

So the direction of gravity (the force F) stays the same when you flip time. I can explain that without the math by pointing out that if you took a video of a ball being thrown up and caught and played it in reverse, it would still depict a ball being thrown up and caught.

Does that make more sense to you?

More on topic, I think our existing theories of reality tell us that the future probably affects the past, or at very least, is predetermined. If you know the solution to a differential equation, you know the state at any point in time. There's no going off the rails, so to speak. And if the system is constrained in any dimension (i.e. it's nonholonomic) then the state at any given moment relies on the full trajectory up to that point, as opposed to just the previous state. But you can flip that on its head and say that the future state determines the present trajectory. E.g. to turn a bicycle left, you have to first turn right.

Our brains like to process events in a linear sequence, from past to present to future, but this view of time might not fully capture how everything in the universe is interconnected. It's possible that our language just can't handle these complex concepts.

So, I don't think anything mentioned in this thread contradicts the idea that "time always moves in one direction" and "entropy always increases".

I'll expand here how if the arrow of time actually doesn't exist, the future could change the past without breaking our - current - understanding of physics (tragiclly because we will probably have maybe hundred of years till we change our minds about what are the properties of the universe).

In a range or probabilities of one event, one of the probabilities will always be the one is going to actually happen. Closer to the event to occur the most certain you can be about which one of those, could be the one that will happen.

Here's the catch, you have to change your mind a bit, in our current understanding of physics, the information of the future event which has not happen yet, already exists here in the past for that event.

Now, if you know - and you know - the outcome of an event, you most certainly will be able to choose if you go along that path, or you choose to change the future event to something else. Whoalá, the future changed the past.

Brains of earth continously do this, every second of our entire lives, animal brains do this too, almost all life on Earth has some neurological, physiological, chemical predictive mechanism in place.

An example, you're about to walk across a street, you see a car coming, now your brain "predicts" you'll be hit by that car if you just keep walking, you stop walking to avoid certain death, done, the future changed the past. The information - really close to 100% of probability of death - extracted by the brain from the sheer reality of the universe, allowed you to survive.

And no current understanding of physics got harmed anywhere along the way of the future changing the past.

So no, it's not at all incompatible with retro-causality. When you think about retro-causality, the idea that time "moves" is completely superfluous. Time is probably not even a real thing.

Incorrect. The out of atmosphere color temperature of Sol is ~5900K. The average color temperature of the Milky Way is 4700-5000K.

https://www.news.pitt.edu/milkywaycolor

Marbles in a jar are not arranged in a neat spacial grid, but in all kinds of configurations.

The chance of recovering any near perfect starting symmetry, depending on the size of a jar, might take decades or millions, or more years.

In the meantime, all that energy being used to shake the jar is generating huge amounts of heat entropy.

It is possible that that the original expansion, inflation, and even dark energy are also driven by thermodynamics, but we just don’t know that.

Everything we do takes advantage of the higher to lower entropy gradient.

We get relatively organized photons from the sun, a percentage get stored in wood of trees, so we can burn that for heat which can drive an engine or generate electricity, with the end result is doing some useful work.

And we don’t actually lose any energy, due to conservation of energy.

But we have now lost USABLE energy, because all our captured energy is now heat diffusely spreading out from our engine into the atmosphere where it becomes uncontrolled DISORGANIZED and therefore no longer usable.

So clear causes tend to occur in past of clear effects.

For large objects.

But again, if you watch videos of individual marbles bouncing around, forward or backward, you see just as clear chains of cause and effect in either direction.

Exactly. It doesn’t take a very large jar to make a return to an original state practically impossible. But even for two marbles, shaking them to return them to their original locations costs a fair amount of organized energy.

And that is organized chemical energy in your muscles, which you are dissipating as disorganized heat energy due to your efforts, increasing the total disorganization.

And the marbles are microscopically wearing down, shedding compounds. The jar is also wearing down. Both becoming less organized.

So even with two marbles, overall entropy continues increasing.

We can locally reverse entropy, only at the cost of actually increasing entropy in total.

- Organizing your day takes effort and uses up useful organized energy.

- Computation uses up useful organized energy.

- Your cells, maintaining their metabolism, uses up useful organized energy.

No matter what we do, entropy still increases.

(0.00..0..1 = 0 just as 0.99 repeating equals 1)

IIUC my professor right the probability is non zero but is practically impossible for a large number of incompressible spheres.

Holographic universe is that the physics and information in a 3+1D space time could be encoded into a 2+1D universe (with it's own physics).

I often find them insightful, especially if I am reviewing them again years later.

*: On "utilize". A central debate (the central debate?) seems to be what sort of "state access mechanism" this maps to in our lexicon: "{reading|writing} {global|local|shared} {bandwidth|memory}"

Technically, casualty required that anyway. My understanding that it's infinity in space, not time that matters here. i.e. predicting your decision to have a ham sandwich may require predicting the entire universe and since we're part of the universe and can't look from 'outside' that decision would be unpredictable from inside the universe.

>And yes, provability is a major problem with all these kinds of theories.

I think showing that quantum effects are negligible for human brains would do, at least regarding your decision to have a ham sandwich?

To the second question, yes. It's beyond comprehension and wondrous. It's maximum novelty and total absurdity.

The comment that superdeterminism requires a higher-order determinism, which itself requires a yet-higher-order determinism... I think you're confusing it with a causal mindset. If the universe is effectively a recording, why does it need any ultimate cause? Causal thinking would only make sense from a perspective within that recording.

Of course we want to know "why is any of this here?" But what if the ultimate question doesn't actually have an answer?

But there's a difference between "screaming into the void", like broadcasting radio waves, that presumably have 0 effects, and other things.

As a collection of probabilities stored as a wave.

If a bank account has a 50% probability earning a penny every second, the bank doesn't need to store all of the intermediate values for every "clock tick", but instead calculate how much has accumulated since the last time someone checked the account and store that value with a timestamp.

Not existing is the cheapest.

Then, broad strokes, location and orientation

Then pieces, level of decay

etc,

and moving between the layers is you spending your attention budget to force the universe to do more work.

Perception and reality are not in fact the same thing.

If you were not there and didn’t not commit the crime, is that past to which used to determine your conviction factual?

Whether later you are proven not guilty, the past didn’t change, but rather our perception of it.

To make this no longer be (at some point in the future) the state of affairs, how could it be done (make it "in fact")?

"Why not?" seems like a decent first attack to the problem - why are physicists (or, scientists in general) so bad at philosophy? For one, I would nominate the "When you have a powerful hammer, everything looks like a nail" psychological phenomenon, as one plausible part of the puzzle.