A fundemental flaw in physics?

  • Thread starter maximus
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i'm not quite sure if this belongs in this forums, but i've been wondering. how can we ever truly know something? are we right in calling an event a law of science that cannot be avoided simply because we repeatedly observe that event in an experiment? or, more simply, if we drop a stone a hundred times to the earth how can we ever know -truely know without a doubt- that it will fall again the next time? i'd imagine this could qualify as a fundemental flaw.
 

LogicalAtheist

What? Fundamental FLAW? More like fundamental LAW.
 
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Originally posted by LogicalAtheist
What? Fundamental FLAW? More like fundamental LAW.
ahhh... a paradox!
in my terms to describe it as a LAW is contradictive because one can never know. (yes i relieze that this comment can spin on and on and on)
 

damgo

Originally posted by maximus
i'm not quite sure if this belongs in this forums, but i've been wondering. how can we ever truly know something? are we right in calling an event a law of science that cannot be avoided simply because we repeatedly observe that event in an experiment? or, more simply, if we drop a stone a hundred times to the earth how can we ever know -truely know without a doubt- that it will fall again the next time? i'd imagine this could qualify as a fundemental flaw.
Yes... this "problem of induction" was first raised by David Hume back in the 1700s, and it's been a central problem in philosophy, especially philosophy of science, ever since.

Course, in the real world, we just assume the laws of science aren't changing on us, just like we assume the sun is going to rise tomorrow...
 

Ivan Seeking

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Re: Re: a fundemental flaw in physics?

Originally posted by damgo
Yes... this "problem of induction" was first raised by David Hume back in the 1700s, and it's been a central problem in philosophy, especially philosophy of science, ever since.

Course, in the real world, we just assume the laws of science aren't changing on us, just like we assume the sun is going to rise tomorrow...
As much as we know that one day it won't.

I think this question becomes more significant at deeper levels. Surely it does at the deepest levels where things like Gödel’s theorem could even sneak up to haunt us. In case our friend maximus is unfamiliar with this, Gödel’s Incompleteness Theorem basically shows that even mathematics cannot prove itself true.
 
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Re: Re: Re: a fundemental flaw in physics?

Originally posted by Ivan Seeking
As much as we know that one day it won't.

I think this question becomes more significant at deeper levels. Surely it does at the deepest levels where things like Gödel’s theorem could even sneak up to haunt us. In case our friend maximus is unfamiliar with this, Gödel’s Incompleteness Theorem basically shows that even mathematics cannot prove itself true.
physics is trial and error
if there had some except for the Law
then we should make a change for the Law
until now the sun is rise every day , no esception
so it's still a Law....not a flow
 
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Einstein said:" the most incomprehensible thing about the world is that it is comprehensible."
if you believe the world is comprehensible
then you should believe physics
if the sun was raise at yesterday and raise today , but tomorrow not......than the world is incomprehensible
but this is never happen in our world
so i believe physics
 

Ivan Seeking

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Originally posted by newton1
Einstein said:" the most incomprehensible thing about the world is that it is comprehensible."
if you believe the world is comprehensible
then you should believe physics
if the sun was raise at yesterday and raise today , but tomorrow not......than the world is incomprehensible
but this is never happen in our world
so i believe physics
He probably said this in opposition to the philosophies of Quantum Mechanics. On this point, it seems he was wrong. :smile:
 
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Firstly, we never stated that we know EVERYTHING. So if for instance the law of gravity works different then we described using the laws of gravity (GR), this would merely necessitate us to design a new theory, that matches observed facts.
And the only reason for doing that is when we observe things, that can not be explained based on the existing laws.

So in fact your problem you state, is not even a theoretical problem, but a practical one. It happened over and over in physcis.
For instance Newton mechanics had to be replaced by relativity, to macth observations. Although in this case, the theory became before the observational proof.

I think you ponder about what are the fundamental laws, and can we ever know them. The answer is that we proceed from relative knowledge and truths, and may find better knowledge and truth, but never absolute truth.
In this sense, we never find absolute or fundematental laws, only relative laws.
 
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Originally posted by Ivan Seeking
He probably said this in opposition to the philosophies of Quantum Mechanics. On this point, it seems he was wrong. :smile:
haha....
you say quantum mechanics is incomprehensible
i think you should more work hard to understand it
quantum mechanics is tell us the probability
but not incomprehensible of the world
 

Ivan Seeking

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Originally posted by newton1
haha....
you say quantum mechanics is incomprehensible
i think you should more work hard to understand it
quantum mechanics is tell us the probability
but not incomprehensible of the world
now, now, I still have Feynman in my pocket:
Anyone who understands Quantum Mechanics hasn't studied it long enough
We can say how many of a million suns may rise, but as for ours I fear the morn.
 
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Originally posted by Ivan Seeking
now, now, I still have Feynman in my pocket:


We can say how many of a million suns may rise, but as for ours I fear the morn.
quantum mechenics show us the so unpredictable of the world
but we still can describe why it will happen
that mean it still comprehensible
i think you should know what more about how the quantum theory working,
you will know what the Feynman means
 

Ivan Seeking

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Originally posted by newton1
quantum mechenics show us the so unpredictable of the world
but we still can describe why it will happen
that mean it still comprehensible
i think you should know what more about how the quantum theory working,
you will know what the Feynman means
Well, I have mostly been joking but:

When will an isotope decay?
What is the physical mechanism for entanglement?
Please describe the exact physical nature of an electron in a superposition of eigenstates.

We have words for ideas that can be expressed mathematically. We have a tremendously successful model [QM]that is sometimes called more successful than all previous theories combined. This does not mean we understand it. You don't agree?
 
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Originally posted by Ivan Seeking
Well, I have mostly been joking but:

When will an isotope decay?
What is the physical mechanism for entanglement?
Please describe the exact physical nature of an electron in a superposition of eigenstates.

We have words for ideas that can be expressed mathematically. We have a tremendously successful model [QM]that is sometimes called more successful than all previous theories combined. This does not mean we understand it. You don't agree?
yes...
but i am discuss how many we understand about the world
i know there have many thing we still need to understand
but it doesn't mean it can not be understand
i just say the world is comprehensible
will you see the electron will suddenly become a proton??
will you see the sun suddenly raise on west ??
this call comprehensible
 

Ivan Seeking

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Originally posted by newton1
yes...
but i am discuss how many we understand about the world
i know there have many thing we still need to understand
but it doesn't mean it can not be understand
i just say the world is comprehensible
will you see the electron will suddenly become a proton??
will you see the sun suddenly raise on west ??
this call comprehensible
We agree. :smile:
 

drag

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Originally posted by maximus
or, more simply, if we drop a stone a hundred
times to the earth how can we ever know -truely
know without a doubt- that it will fall again
the next time?
We don't, but it seems likely. :wink:
Also, it is the only possibility that
we can explore in this case because other
possibilities are essentialy infinite and
we don't have any preferences amongst them.

Live long and prosper.
 
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marcus

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Ivan I would like to know you better. I like how you put these two things. The Feynmann epigram in the pocket. And the nearly iambic sound of the "fear the morn" line----is that a quote from somewhere or do you just put a literary touch on things now and then? this is a nicely tossed off post:

**********

now, now, I still have Feynman in my pocket:

quote:
--------------------------------------------------------------------------------
Anyone who understands Quantum Mechanics hasn't studied it long enough
--------------------------------------------------------------------------------



We can say how many of a million suns may rise, but as for ours I fear the morn.

************

As for the original question, this was solved by Bayes was it not?

I suspect as a philosophically sophisticated person you must know the Bayesian inference model.

this is already a long thread and no one has told maximus about
that way to resolve his difficulty

Were you the person who wandered into the Astronomy game with a neat question about the event horizon a few days ago. I confuse names, but I think it may have been you
 

Ivan Seeking

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Originally posted by marcus
----is that a quote from somewhere or do you just put a literary touch on things now and then? this is a nicely tossed off post:
Thanks. No just me. I get a little philosophical from time to time...especially at 3AM

[B}As for the original question, this was solved by Bayes was it not?
I suspect as a philosophically sophisticated person you must know the Bayesian inference model.

this is already a long thread and no one has told maximus about
that way to resolve his difficulty

Were you the person who wandered into the Astronomy game with a neat question about the event horizon a few days ago. I confuse names, but I think it may have been you [/B]
No that's news to me. I will read up on this. And yes I'm the troublemaker with the event horizon problem. In the end, I wasn't sure if this interpretation is correct or not. Someone objected claiming this is merely a matter of semantics
 

marcus

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Originally posted by Ivan Seeking

...I wasn't sure if this interpretation is correct or not. Someone objected claiming this is merely a matter of semantics
Not to worry, the person might have said "semantics" and meant "sour grapes".

Originally posted by Ivan Seeking
No that's news to me. I will read up on this...
Bayesians are a minority among probability theorists, but a respectable one. For many years the most eminent prob. theorist/game theorist at UC Berkeley was a Bayesian named
Blackwell.

I cant give anything but the most simplistic account. A Bayesian begins dropping bricks with an arbitrary probability distribution according to which the brick might just as well fall upwards. Each time he does the experiment he recalculates his probability distribution (which becomes a way of describing his info about the world or his beliefs about physical law or his expectations of what will happen). he uses a calculus of "conditional probabilities" developed by Bayes----who thought this was all highly sensible.
The more he drops the brick and recalculates his subjective probabilities describing his expectations the better they get.
Bayes and the Bayesian school make this sort of rigorous and prove theorems about it. Superficially or at first sight it may seem
----well----either dumb or obvious. But that may be mostly because of my shallow view of it. I dont know any books to read about Bayesian theory.
 

Ivan Seeking

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Originally posted by marcus
Not to worry, the person might have said "semantics" and meant "sour grapes".



Bayesians are a minority among probability theorists, but a respectable one. For many years the most eminent prob. theorist/game theorist at UC Berkeley was a Bayesian named
Blackwell.

I cant give anything but the most simplistic account. A Bayesian begins dropping bricks with an arbitrary probability distribution according to which the brick might just as well fall upwards. Each time he does the experiment he recalculates his probability distribution (which becomes a way of describing his info about the world or his beliefs about physical law or his expectations of what will happen). he uses a calculus of "conditional probabilities" developed by Bayes----who thought this was all highly sensible.
The more he drops the brick and recalculates his subjective probabilities describing his expectations the better they get.
Bayes and the Bayesian school make this sort of rigorous and prove theorems about it. Superficially or at first sight it may seem
----well----either dumb or obvious. But that may be mostly because of my shallow view of it. I dont know any books to read about Bayesian theory.
If I understand the philosophiical distinction here, we do not attempt to ascribe any particular path or mechanism to determine the result, rather we get a statistical expectation [void of any other philosophy] for any particular final position [destination] of the brick?

Next, do we extend the set of all possible destinations to include those due only to quantum phenomenon - eg the 1:10^50 chance that the brick disappears and turns up elsewhere? The similarities to QED is what hits me like a brick.
 

marcus

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Originally posted by Ivan Seeking
If I understand the philosophiical distinction here, we do not attempt to ascribe any particular path or mechanism to determine the result, rather we get a statistical expectation [void of any other philosophy] for any particular final position [destination] of the brick?

Next, do we extend the set of all possible destinations to include those due only to quantum phenomenon - eg the 1:10^50 chance that the brick disappears and turns up elsewhere? The similarities to QED is what hits me like a brick.
Woah! I did not notice your post until now or i would have replied earlier. The answer is, I simply do not know how Bayesians handle the question of physical laws.

It might be a possible PhD thesis for all I know!

It is a small minority which has been active in Probability Theory for several decades and it seems very likely that by now they have devised methods for placing Bayesian probabilities on the truth of models or laws of nature. But perhaps they have not done this and it is an open area for research.

The trouble is, although I know Blackwell personally, I have always avoided talking about Bayesian probability with him, and
am totally ignorant about it. I know that there is an "if-then" type of object called a "conditional probability" in this theory. I know that one starts by conjecturing a "prior" distribution of probability on states of the world or matters of concern and then revises or improves that prior----presumably thru a calculus of conditional probabilities. It could be very boring! I have always wished to avoid getting deeper into it. It remains a minority school even among probability theorists (a small academic community in the first place!) But who knows, it might eventually become important!

The trouble is, as far as I know Bayesian probability calculus has so far never been made *quantum*------these days who can take probability seriously if it is not done quantum-style? But this is just my take and as I say i do not know the subject.
 

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