Why aren't all processes moving exactly opposite to their present direction? — EugeneW

Why would arguments about time be physicalist?
Time crumbles things; everything grows old under the power of time and is forgotten through the lapse of time; but not wine song and love

Try this experiment: put a bunch of steel ball bearings (representing particles) in a box, shake the box and record a video of the balls moving randomly in all directions. Now, call two friends to your house. Play the video you recorded normally (forwards) to one friend and play the video in reverse (backwards) to the other friend. Ask both of them this question: Was the video played forwards/backwards? They won't be able to answer this question. — Agent Smith

There is a clear direction of time in a box full of moving steel balls. Perhaps you can hide it by continuing to add energy to the box, but the minute you stop the balls will all fall to the bottom.

Time does move backwards; or rather we move backwards through time. You can tell because we can see where we've been, but not where we're going.

It is causality, not time, that has a direction. Time is the space in which causality evolves. If time "ran backwards", we wouldn't notice, because our memories would still be consequent of causally prior events.

[

Time does move backwards; or rather we move backwards through time. You can tell because we can see where we've been, but not where we're going. — unenlightened

Rather, from our perspective, we are moving forward while able only to look backward.

Eyes in the back of your head is it?

Eyes in the back of your head is it? — unenlightened

we are riding in the back of a pickup truck, trying to guess where we are going by looking behind.

M'kay. :mask:

you nicked that off the aboriginals...

There is a clear direction of time in a box full of moving steel balls. Perhaps you can hide it by continuing to add energy to the box, but the minute you stop the balls will all fall to the bottom. — T Clark

Why don't gas molecules behave like steel balls, settle at the bottom of their containers? I believe $CO_2$ does that (vide Grotta del Cane).

It looks like we're on the same page. Great!

Why don't gas molecules behave like steel balls, settle at the bottom of their containers? — Agent Smith

Gas molecules are bound together much more weakly than solid molecules. They bounce quickly around inside any container - off the walls and each other. Temperature is a measure of the molecules' average kinetic energy. The warmer it is, the faster they move. Molecules are also affected by the force of gravity, but I guess the energy associated with gravity is much smaller than the heat energy.

Gas molecules are bound together much more weakly than solid molecules. They bounce quickly around inside any container - off the walls and each other. Temperature is a measure of the molecules' average kinetic energy. The warmer it is, the faster they move. Molecules are also affected by the force of gravity, but I guess the energy associated with gravity is much smaller than the heat energy. — T Clark

Bravo! Muchas gracias señor!

Eyes in the back of your head is it? — unenlightened

:up: Eyes "at" or "in"?

You're wrong. Please don't go spreading your ignorance — T Clark

Again, probability has nothing to do with it. It explains why time goes forward given initial conditions. If a flipped coin lands 10 000 000 times on the floor with heads up, and 2 times on tails, is the reason it lands on heads so often that it has a higher chance? No. The reason is the die itself. Likewise for time. The basic question is why the begin state of the universe is not situated at its end with all motion reversed.

What (I think) I know: Entropy gives time direction. The rule looks to be rather simple: If you're told the entropy is x at time T1, y at time T2 and y > x, then T2 is the future and T1 is the past.

Entropy increasing (2^nd law of thermodynamics) is a statistical law i.e. not true that entropy ALWAYS increases. SOMETIMES it can decrease, when it does, time flows backwards. It's not a question of if, but when (the entropy of the universe will fall and time flows backwards). Hindus, with their cyclical cosmology, seems to have intuited this 5k years ago (vide the vedas). The Phoenix is reborn from its ashes. :smile:

What I (think) I know: Entropy gives time direction. The rule looks to be rather simple: If you're told the entropy is x at time T1, y at time T2 and y > x, then T2 is the future and T1 is the past — Agent Smith

Yes, my beloved! But why not the other way round? Why don't things evolve from the future to the past? Universe starting from a reversed big rip, black holes becoming white, matter and light reversing to condense into a red giant, which gets smaller to become our Sun, Earth appearing, creatures raising from the dead getting younger, entering the womb with a screaming going inside their mouth, buildings torn down, planes flying backwards, the atmosphere getting cleaner, devolution to amino-acids, and finally a big crunch. Could have happened...

I am simple minded; I define 'forwards' as the way I am facing, my eyes being at, in, or on my face. I cannot see where I am going in time, but only where I have come from. Therefore the future is behind me and the past in front of me, and I progress backwards. "At or in?" I give not a fig. "on", why not?

Yes, my beloved! — EugeneW

:brow:

Intriguing questions. If you want to prove that such events couldn't have/can't occur, you might wanna check whether it makes for a side-splitting joke (reductio ad absurdum).

Good luck!

"At or in?" I give not a fig. "on", why not? — unenlightened

Magnifique monsieur/mademoiselle, magnifique! :up:

I just realized - you're telling me to eff off! :grin:

You can tell because we can see where we've been, but not where we're going. — unenlightened

I think this is a very good point, unenlightened. This looking backward in time is fundamental to observation, and the basis of the empirical sciences. But when we turn around, to face the future directly, we are faced with possibilities, anticipations, wants, needs, desires, and the moral obligations of ought. There is what I think of as a wall of non-existence in front of us in time. The future cannot be sensed, nor has it been sensed, and it's as if there is a wall of unintelligibility directly in front of us, which we relate to through prediction.

The act of predicting involves a turning around, from facing the past in observation, to facing the future in anticipation. Any such turning requires a system of orientation to account for the reality of the turn. In our society we seem to be lacking in such a system. It's as if we believe that we can turn back and forth, from past to future, at will, without adapting the principles we apply in understanding, to account for the change in direction. The first step I believe, toward rectifying this, is accepting what you've pointed out, that there is a change in direction, between "where we've been" and "where we're going".

I am simple minded; I define 'forwards' as the way I am facing, my eyes being at, in, or on my face. I cannot see where I am going in time, but only where I have come from. Therefore the future is behind me and the past in front of me, and I progress backwards. "At or in?" I give not a fig. "on", why not? — unenlightened

We need to learn the true orientation, and this is where the mind is looking, not where the senses are looking. The mind looks to the future in anticipation, and the senses look rearward at the past. Therefore we need to adapt the rearward facing principles derived from observation, to be consistent with the true frontward facing direction of the mind, which is the future. The solution is not to try and tell the mind that it is facing the wrong direction, because the senses are facing backward in time, so backward is supposed to be forward. The solution is to understand that the senses are really facing backward.

Again, probability has nothing to do with it. It explains why time goes forward given initial conditions. If a flipped coin lands 10 000 000 times on the floor with heads up, and 2 times on tails, is the reason it lands on heads so often that it has a higher chance? No. The reason is the die itself. Likewise for time. The basic question is why the begin state of the universe is not situated at its end with all motion reversed. — EugeneW

From Wikipedia:

The interpretation of entropy in statistical mechanics is the measure of uncertainty, disorder, or mixedupness in the phrase of Gibbs, which remains about a system after its observable macroscopic properties, such as temperature, pressure and volume, have been taken into account. For a given set of macroscopic variables, the entropy measures the degree to which the probability of the system is spread out over different possible microstates. In contrast to the macrostate, which characterizes plainly observable average quantities, a microstate specifies all molecular details about the system including the position and velocity of every molecule. The more such states are available to the system with appreciable probability, the greater the entropy. In statistical mechanics, entropy is a measure of the number of ways a system can be arranged, often taken to be a measure of "disorder" (the higher the entropy, the higher the disorder). This definition describes the entropy as being proportional to the natural logarithm of the number of possible microscopic configurations of the individual atoms and molecules of the system (microstates) that could cause the observed macroscopic state (macrostate) of the system. The constant of proportionality is the Boltzmann constant.

Yes yes and yes again. The state of gas corpuscules being together in one corner of a container can be realized in way much less ways than them being all over it. That's no issue. The issue is why all motions of particles have the direction they have (which turns out to be compatible with the chances). Why don't they have the opposite velocities, so they meat in a corner?

Yes yes and yes again. The state of gas corpuscules being together in one corner of a container can be realized in way much less ways than them being all over it. That's no issue. The issue is why all motions of particles have the direction they have (which turns out to be compatible with the chances). Why don't they have the opposite velocities, so they meat in a corner? — EugeneW

I took my best shot. Nuff said.

I've decided to write "nuff said" from now on when I think the conversation is over in honor of Stanley Martin Lieber.

Did he die? Almost 100, so I saw on Wiki. If only time run backward.

Did he die? — EugeneW

Alas.

C theory, which rejects temporal directionality. — Kuro

Nobody took this bait.
I cannot find a difference between B and C. B-theorists define directionality based on entropy levels. If the C-theorist denies this, it seems they are in denial of thermodynamic law.

Most of the literature I saw concerning C-theory mistakenly uses A-references in describing B-theory, which is a straw man.

As for the title of this topic "Why does time move forward?", I can only say that it is a problem only for those that posit that time is something that moves, forward or otherwise.

We cannot say if the clock moves forward in time or backward. Its direction is defined in the context of particles evolving towards constellations that change asymmetrically. That is normally towards constellations that have more possibilities to be realized than those preceding them, like the gas corpuscules in a container evolving towards uniform distribution. But this can only happen when the initial distribution ordered, like the state of the plasma after the big bang (which seems to be a disordered gaseous state, buth isn't). Why isn't the begin situated in the disordered state of the disordered state of photons in which the universe finally evolves. The problem is that their momenta, and all other motions had to be exactly the opposite. But if they get a momentum at the big bang, they could also get (a reversed) one, at the big rip. The second law of thermodynamics would then be the inverse of the current one (evolution towards more entropy, constituting forward time):

Second law of TD in time-reversed universe:

All closed physical systems evolve towards lower entropy (with local patches evolving to higher entropy, but these don't constitute time reversion).

I can only say that it is a problem only for those that posit that time is something that moves, forward or otherwise. — noAxioms

Don't the hands of the clock move forward in time? 1 o'clock, 2 o'clock, 3 o'clock... Could be 3, 2, 1. But it isn't.

Second law of TD in time-reversed universe:

All closed physical systems evolve towards lower entropy (with local patches evolving to higher entropy, but these don't constitute time reversion). — EugeneW

It seems like you are saying that, in a time-reversed universe, the system evolves from a more probable state to a less probable one. That...doesn't make any sense.