Why is time apparently assymetrical?
(I.E. causality, arrow of time)
What makes you think that time is linear?
I think the OP refers to the uni-directionality of the dimension known as Time.
You can go left or right, up or down, back or forth, but only one way in time; toward an unavoidable future and away from an irretrievable past.
think of it this way. is the earth’s orbit symetrical even though our (people stuck on this ol’ rock) direction and speed are fixed? same with time. it seems to me that the forced march through time could be speeded up/ slow downed reversed, and stuff if we would something to push off in time. a temporal rocket of sorts. you want to make your brain throw off illegal errors? try trying to time as just anther spaciel dimention with everying happing at once. then trying to make a mentle model of time the accomidates both time (dimention) and our experance of time (clock). it just does not work to well.
would something should be had something
try trying to time should be try trying to think of time
darn typos
It’s a question people continue to argue over and so there currently isn’t a widely acknowledged correct answer.
Arguably the most successful attempt at reaching a consensus position amongst physicists was The Physics of Time Asymmetry (Surrey, 1974) by Paul Davies, in the days just before he started writing popular science books. His argument was that all the different arrows of time that had been identified could be traced back to the fact that the universe had a beginning. His rather optimistic conclusion was that this settled the matter as far as physics was concerned, though there was still stuff for the philosophers to bicker over.
In the event, while admired as a good review of the issues, Davies failed to end the debate and it’s rumbled on. Not least because developments in quantum cosmology and ideas about reversable computation have added new slants to it. And for good measure, we have philosophers claiming that the physicists have completely misunderstood the question. That’s the position of Huw Price in Time’s Arrow and Archimedes’ Point (Oxford, 1996). I haven’t read it yet, but physicists generally tend not to have been convinced by his overall thesis.
I should add that it’s one of those questions, like interpretations of QM, that makes very little difference in practice. Most physicists - myself included - probably don’t have terribly strong opinions on the matter.
I believe it was Steven Hawking that said in one of his books that the only difference between the past and the future is which one we remember.
Time isn’t some stuff flowing by. That’s just an illusion.
Time is the agency which ranks causes before effects and effects after causes.
Our brains perceive it as stuff flowing by because the brain is the organ that manages cause and effect.
You either have to expect time to be asymetrical, or you have to believe there are no causes and no effects.
At least, that’s what I think…
Perhaps time is running backwards? If it were, how would we know?
Entropy. Pick a universe, any universe. Look at which way entropy is increasing. That’s the positive time direction.
“Temporal direction of generally increasing entropy = increasing time” may be a useful definition, but the equations of physics itself work equally well in either direction. Thermodynamics would work as well in reverse with the expected change in entropy reverse. Particles are equally well represented as the corresponding antipaticles going backwards in time. Etc.
I think the anthropic principle alluded to by Napier and lucwarm comes closest to the truth. Spacetime is not assymetric. We simply experience causality in terms of increasing entropy, and therefore define time and causality according to our perception. No hard physical principle would be violated by interpreting a given spacetime in the other direction. Events in such a interpretation would simply seem completely counterintuitive to us
Why do we percieve time in the direction we do? What sort of science (e.g. evolution) would arise if we viewed it in the other direction? I really couldn’t say – but contemplating the ‘explanations’ we might have if we did is potentially enlightening.
*By definition, * time runs forward. Otherwise, what exactly do you mean by “backward”?
Let’s not forget, the concept of “time” was developed by Mankind.
Even assuming that the flow of time is an illusion, that doesn’t dispense with the fact that time is assymetrical: we have information about the past, we don’t have information about the future.
Also, although you can quibble about “reversing” time in the sense that you could switch the labels “past” and “future”, that doesn’t change the fact that you can’t have time running both ways at once. That introduces things like violating causality.
Actually, the interesting thing about Quantum Mechanics is that the equations are not assymetrical wrt time, and the “forward” direction of time is a constrain that has to be [artificially] added after the fact.
Time is an illusion created by motion. We perceive that matter/energy must be in a particular state “before” it exists in a consequent ( or actually in a proximal state) and our brain stacks the perceptions of change giving the illusion of “time”. This is why we have trouble conceiving of a beginning and conceiving “infinity”. The essence of the universe is change, motion, instability. A mind which comes temporarily into existence, which is capable of reflecting the phenomena of eternal transmutation in a discrete portion of the whole infinite flux, will have the illusion of a ‘beginning’ and an ‘end’.
It may be impossible to comprehend because we are programmed to not comprehend it but the truth may be this: there is something called ‘consequence’ which happens because energy/matter cannot be created or destroyed - it must exist in one state “before” it can exist in another.
But there is not a great “river”, separate from motion, flowing in a direction.
All there is is the “Now”, a now that has the essence of constant change.