Thread: A question about entropy

From a given initial condition (the present) would not entropy (the increase in disorder) work backward in time as well as forward? How is it that we infer the past to have been more orderly than the present? Or do we? This question came to mind while entertaining the various popular scenarios about time travel, but it may have a more serious side. Why do we expect to find the same kind of a past that we remember? By that I mean recorded past as well, since we only have the record, not the original. I would presume that the past would be no more or less certain than the future we anticipate. The probability of an anticipated outcome would be similar to the probability of something actually having happened.

As time goes entropy increases as disorderness increases...its all depended on time.S=(f)t...where S is entropy...your question gets interesting here...we do not have the 'original past' there is no original...certain events happen in the past that changes the course of the present. And i pressume that it is thoes events in the past that we have record of...

I am glad you find this interesting. So do I.
You said:"certain events happen in the past that changes the course of the present." I would say that certain things happen to bring about the present as we find it to be. I am not at all sure that a place like the past exists, or that there is a course in progress that is somehow being changed. Every event happens in its own present. If it leaves an effect of some noticable duration, we may consider that to be a record from which we can ascertain its cause.

Originally Posted by Daedalus

From a given initial condition (the present) would not entropy (the increase in disorder) work backward in time as well as forward? How is it that we infer the past to have been more orderly than the present? Or do we? This question came to mind while entertaining the various popular scenarios about time travel, but it may have a more serious side. Why do we expect to find the same kind of a past that we remember? By that I mean recorded past as well, since we only have the record, not the original. I would presume that the past would be no more or less certain than the future we anticipate. The probability of an anticipated outcome would be similar to the probability of something actually having happened.

We infer the past to have been more orderly than the present by making observations, such as those which led to the laws of thermodynamics. For example we observe that systems tend to reach thermal equilibrium. A system in thermal equilibrium is more disordered (higer entropy) than one in which there is a temperature difference. I don't understand the rest of your question.

You realize that not all choices or actions that shapes the future,but you will then see that there is no present without the past,although the past then seems like an illusion...just like visualizing the difference between the 2oclock of 1999 and that of 2012. What are the difference? 2oclock is written as 2oclock at all times.the difference is you that age...you see the time differently.

You realize that not all past choices or actions that shapes the present,but you will then see that there is no present without the past,although the past then seems like an illusion...just like visualizing the difference between the 2oclock of 1999 and that of 2012. What are the difference? 2oclock is written as 2oclock at all times.the difference is you that age...you see the time differently.

Originally Posted by Daedalus

Why do we expect to find the same kind of a past that we remember?

You found a PAST? Congratulations! What did you do with it?

Originally Posted by Harold14370

Originally Posted by Daedalus

From a given initial condition (the present) would not entropy (the increase in disorder) work backward in time as well as forward? How is it that we infer the past to have been more orderly than the present? Or do we? This question came to mind while entertaining the various popular scenarios about time travel, but it may have a more serious side. Why do we expect to find the same kind of a past that we remember? By that I mean recorded past as well, since we only have the record, not the original. I would presume that the past would be no more or less certain than the future we anticipate. The probability of an anticipated outcome would be similar to the probability of something actually having happened.

We infer the past to have been more orderly than the present by making observations, such as those which led to the laws of thermodynamics. For example we observe that systems tend to reach thermal equilibrium. A system in thermal equilibrium is more disordered (higer entropy) than one in which there is a temperature difference. I don't understand the rest of your question.

I have no issues with the second law of thermodynamics. Repeated observations have confirmed it, and that's fine with me. I understand thermal equilibrium as much as any layman might. I guess I'm hung up on what is meant by order and disorder.
When I knock over a stack of blocks, there are many ways that the blocks could fall, and it is unlikely that they would ever fall back into the same stack. But when I look at a pile of blocks, there as just as many ways that they could have been stacked, if they were stacked at all. So what can I infer about the past from my observation?

Originally Posted by sigurdV

Originally Posted by Daedalus

Why do we expect to find the same kind of a past that we remember?

You found a PAST? Congratulations! What did you do with it?

No.I was only expecting to, but it was not there.

There have been an argument of philosophy. That says,you cannot tell the outcome of an event or experiment without experince(record) of the past once....that is, without konwing of gravity or that wathever goes up must come down,if i throw a stone up,you cannot tell me without experince that the stone would fall.

Originally Posted by merumario

There have been an argument of philosophy. That says,you cannot tell the outcome of an event or experiment without experince(record) of the past once....that is, without konwing of gravity or that wathever goes up must come down,if i throw a stone up,you cannot tell me without experince that the stone would fall.

OK, experience. In other words repeated observation that would establish this as a recurring phenomena of nature. More likely to have happened before, and continue to happen again. But what about non-recurring events ? Is there a method by which science can account for them as anything other than random background noise?

An example:
Non-recurring event: the Big Bang. Do we know why? no. Is it random background noise? no. Can we speculate/make guesses/theorize about it? yes.

during the process of answering with theories, we are already putting experience into play. if there was no questions asked,no answer attempt,and somehow the big bang occurred again, we would not know why. because there is no theory,no experience. so you see msfwan,what we are currently doing is to create a theory to help answer our questions.once our questions are answered,we keep records and it then becomes an experience. and next time we would know why and what a similar big bang would like.

Why do we expect to find the same kind of a past that we remember?

I don't know what you are trying to get at, but the above question is an interesting one.

I guess I'm hung up on what is meant by order and disorder.

Order and disorder are rather non-scientific terms in this context. Just use entropy instead - it is defined as being a measure of the number of possible microscopic states of a system. Now, the thing to remember here is that the most probable macroscopic state of a system is the one with the greatest number of corresponding microscopic states. This is, by definition, then also the state with the greatest entropy. Thus systems will tend towards increasing entropy.

We are not expecting we are being catious.

Maybe he means something like, how do we know what we observed really happened - like maybe we are in the Matrix? Or maybe, how do we know the same thing will happen in the future that we observed in the past?

Originally Posted by Daedalus

Originally Posted by merumario

There have been an argument of philosophy. That says,you cannot tell the outcome of an event or experiment without experince(record) of the past once....that is, without konwing of gravity or that wathever goes up must come down,if i throw a stone up,you cannot tell me without experince that the stone would fall.

OK, experience. In other words repeated observation that would establish this as a recurring phenomena of nature. More likely to have happened before, and continue to happen again. But what about non-recurring events ? Is there a method by which science can account for them as anything other than random background noise?

NO! (I dont think there should be such events. Must be some principle at work.)

Harold,that view is much more better..we keep details,theories,events, our brain does this even if we do not write it down or so...we have the experience and information storage as our property.

Originally Posted by Harold14370

Maybe he means something like, how do we know what we observed really happened - like maybe we are in the Matrix? Or maybe, how do we know the same thing will happen in the future that we observed in the past?

I am approaching this from the premise that what we observe comes as a result of our interaction with it. There are no outside observers. (There might be a name for this sort of perspective.)

In a laboratory experiment, one takes in consideration the effect that the instrument may have on a measurement. Likewise I am questioning how much of what we attribute to the world may be an artifact of our understanding. I am not attempting to say this in the broad sense that everything is. Just looking at some particulars. In this case the notions we have about the past and the future. Why we tend to think of the past as somehow more fixed while the future is seen as a probability. We can not observe either one directly, though we infer certain things about them.

merumario here is pursuing the notion that the past may be an elaborate record keeping system.
I was looking into how we access such a library, which is why I was mumbling about things like reverse entropy.

I don't like the Matrix analogy because it presupposes a realer reality. It's hard enough to understand this one.

An external observer would have to see the system different,but maybe our own approximation could help see things in another perspective.to an external observer we become part of the experiment..the notion of free will and causality would be considerd alot.

To an external observer we would be part of the experiment, but he is not there. We are a part of our own experiment. I don't think that notions of free will pertain to this topic.

To an external observer we would be part of the experiment, but he is
not there. We are a part of our own experiment. I don't think that notions of free will pertain to this subject.

Of course it does. If theres really a creator,then he should be an external observer.if he knows our future before the present then he has predestined us,hence no free will. It becomes more complex to tell if our actions are not caused by some being or anyother thing. To an external observer,it becomes easy to tell if our actions are willing or not.

Originally Posted by Daedalus

I am approaching this from the premise that what we observe comes as a result of our interaction with it. There are no outside observers. (There might be a name for this sort of perspective.)

Solipsism.

Originally Posted by Harold14370

Originally Posted by Daedalus

I am approaching this from the premise that what we observe comes as a result of our interaction with it. There are no outside observers. (There might be a name for this sort of perspective.)

Solipsism.

Ouch! I would have preferred Relationalism.

Originally Posted by Daedalus

I am questioning how much of what we attribute to the world may be an artifact of our understanding.

I think Kant thought in that way... That we percieve things according to how we are constructed.Why dont look him up?

Originally Posted by merumario

If theres really a creator,then he should be an external observer.if he knows our future before the present then he has predestined us,hence no free will.

Suppose theres a god, that has predestined us and that we can communicate. Then I ask him:Whats the answer to my next question?
Then if he gives x as an answer I will ask any question not having x as an answer.
This shows that at least one supposition was wrong.
Either there is no god or we have free will

I disagree.the question is,why did you ask a question at first? Whatever it is,the creator knows you will ask.and He knows that his answer would be x and then you will ask again.in so doing,he alter the series of questions,which then forces you to ask about x again.which was not what you might have planned.

Originally Posted by merumario

I disagree.the question is,why did you ask a question at first? Whatever it is,the creator knows you will ask.and He knows that his answer would be x and then you will ask again.in so doing,he alter the series of questions,which then forces you to ask about x again.which was not what you might have planned.

You mean he changes things. Then where did the predetermination go?
I ask my first question to prove that at least one assumption is wrong!

The second question can be formulated at the same time as the first.
Then god cannot change anything:

1 What is the answer to question number two?

2 What question has not the same answer as question number one?

Note that if the answer to 1 is the question "x" then the answer to 2 should be a question not having x as an answer.
So it cant be x itself. but if so then x is not a correct answer to 1. The questions simply dont both have a true answer!


But god cannot give that as an answer to the first question because if he does that
then there are many questions not having the answer that there is no answer.
But they all makes the answer to the first question false!

Post Scriptum: In a sense the above proves our free will
since we can want there to be truthful answers to both questions ...

Your freedom does not start at some certain point and ends at another..having no free will does'nt mean you cannot act freely. It means all your actions can be traced to one cause. Whatever then follows is the effect. There is no effect without a cause,unless you want to rewrite the laws of physics...ask yourself why you are here.why you were created.