wrote in message
ups.com...
| What the heck is "BHOT". Being a physicist posting in a physics
| newsgroup, I know about H&R's FOP ,S&Z's UP and even R&W's POTA, but
| what the heck is BHOT?
|
| Harry C.

"A Brief History of Time" by phuckwittor Hawking.
Androcles

TomGee wrote:
I wonder if anyone else has had some doubtful moments as I have had
regarding a passage in "ABHoT", Ch. 9, page 146?

In the last sentence, 2nd-to-last paragraph, Prof. Hawking states,
"When the cup was broken, they would remember it being on the table,
but when it was on the table, they would not remember it being on the
floor."

Hawking, being another crank like Einstein, never learned logic. he
does not understand the concept of necessity and sufficieny. What he
describes is necessary but not sufficient for not having time reversal.
There may be other processes, mechanisms, etc. that prevent humans
being aware of time reversals. For instance, Russell once said that one
cannot prove that the world was not created 5 minutes ago with all the
artifacts and memories necessary so we think it has been there for a
long time.

Of course, Russell was a logician whereas Hawking is just a crank.

Mike




It seems that the latter effect he describes is opposite to that which
should ensue if disorder would decrease with time. I.e., if in the
future a cup we are looking at in the present falls off the table and
breaks, and entropy is decreased during the time we saw it and until it
fell, it seems we should remember it having been on the floor first and
at some time after that, we must see it on the table unbroken.

If the analogy is to stand, we must see the cup unbroken once and
broken afterward when entropy increases, and we must also see the cup
broken once and unbroken next. It seems to me that we must see the cup
broken and unbroken in both directions of entropy in order for the
analogy to be properly compared.

So, Mike, did he say it wrong and it got past the editors, or did he
say what he really thinks? Was it just simply an error he did not mean
to make, or was it perzacly what he meant to say?

Or did he say it correctly and I am reading it wrongly?

"Mike" wrote in message
oups.com...
| Hawking, being another crank like Einstein, never learned logic.

Let's be fair, Mike. He admitted last Thursday on BBC's Horizon
programme
that he was wrong. I expect it will be shown on PBS's "Nova" in a few
weeks.
Hawking's greatest mistake was allowing his first wife to wheel his
gurney
away when I offered to buy him a beer down at Sussex U.
I could have straightened his sorry arse out 31 years ago but he was
pussy whipped.
Androcles.

TomGee wrote:
So, Mike, did he say it wrong and it got past the editors, or did he
say what he really thinks? Was it just simply an error he did not mean
to make, or was it perzacly what he meant to say?

Or did he say it correctly and I am reading it wrongly?

Well, a couple of things:

First, IMO he confuses cognitive perceptions of time with some
allegedly physical quantity of time. Second, he uses the naive knownb
argument which attempts to ground the impossibility of time reversal (
even though the equations of motion are symmetric in +- time), to
cognitive perceptions.

The issue is neither the fact that we do not remeber the broken cup and
then see it on the table, nor the reversibility of equations of motion.
The problem is, nobody knows what time is, and whether it is a
fundamental physical quantity, although it is treated like that in
physical models.

For example, the current argument about time reversibility and
specifically time travel is that it is possible to do so but even if
someone goes back in time, something will happen that will prevent her
from altering the state of the world.

I think Hawking should come out public and ask for forgivness for the
many naive things he has said and written about.

Mike

TomGee wrote:
I wonder if anyone else has had some doubtful moments as I have had
regarding a passage in "ABHoT", Ch. 9, page 146?

In the last sentence, 2nd-to-last paragraph, Prof. Hawking states,
"When the cup was broken, they would remember it being on the table,
but when it was on the table, they would not remember it being on the
floor."

It seems that the latter effect he describes is opposite to that which
should ensue if disorder would decrease with time. I.e., if in the
future a cup we are looking at in the present falls off the table and
breaks, and entropy is decreased during the time we saw it and until it
fell, it seems we should remember it having been on the floor first and
at some time after that, we must see it on the table unbroken.

If the analogy is to stand, we must see the cup unbroken once and
broken afterward when entropy increases, and we must also see the cup
broken once and unbroken next. It seems to me that we must see the cup
broken and unbroken in both directions of entropy in order for the
analogy to be properly compared.

xxein: 'So the disorder would increase with time as opposed with the
disorder decreased with time' (as he states in a nutshell). I see your
point.

He does seem to have ventured into his own fantasy. He uses 'time' as
the order of events and then tries to re-invest it as an 'entropy only
time'. How sad.

It would help those without a copy of his book to have included the
three relevant paragraphs, verbatim. Or more?

It may be sad, also, that we all think we know things. It is even
sadder when we have no doubt.

Chow.

x..., I was concerned with copyright abuse. I paraphrased as much as I
could, hoping I had explained it well. I was not sure I was reading
the book correctly, too. I thought I may be missing something in the
passage. I think he meant to say it right, but he he or his helpers
got it wrong, I think. It does not affect his idea, it is just that he
explained his idea in a wrong way.

Why hasn't anyone else discovered the error, I thought to myself.
Maybe because I am wrong in my comprehension of what he is saying. I
struggled with it off and on and finally decided to ask others about
it.

I may still be wrong, but it seems to me that his example is invalid
because it could not occur and because even assuming it could occur
(all's fair in love and theoretical physics), the observers would first
see the broken cup and not remember it being on the table (Hawkings
claims they would remember it being on the table), and next see it
being on the table and remember it being broken on the floor. Since
time is running backward, the present is the past (broken cup), and the
future comes later (unbroken cup). Hope that helps, as it's confusing
as hell.

From my understanding, if time went backwards, then our memories will
also be backwards: we will remember things before they happened and
forget them once they happened. That is exactly what is described in
the book. What it means is, time may or may not already be going
backwards but we will not be able to observe it since our perception is
still to see the cup on the table then later broken on the floor. What
he's saying is it doesn't matter which direction "actual" time is
flowing. What matters is the direction entropy is flowing.

That's what's nice about cybernetics. You don't even entertain the
thought that time can flow backwards. It adopts physical
constructivism. It's the difference between living in a Spielberg
fantasy world and one where you actually achieve things.

Androcles wrote:

[snip]

Hawking's greatest mistake was allowing his first wife to wheel his
gurney
away when I offered to buy him a beer down at Sussex U.
I could have straightened his sorry arse out 31 years ago but he was
pussy whipped.

What other reason could there possibly be for him
to refuse an invitation from such a charming fellow
as you?