Some Philosophical Arguments

Bertha Huse said:
What do you mean by arbitrary bifurcation?? Not sure I follow you here.
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An arbitrary number of alternate histories of the universe.

Interesting quote. I'm not sure I'm all in with Babinski here. Certainly many philosophers deal with empirical data right? It's not like many philosophers ignored science? And certainly there are many things still unknown in science that are areas of investigation and discussion. Although I agree with you, that we here are probably not going to make any kind of scientific break-thru on these forums.
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I think many philosophers ignore science. But then there is this relatively recent development:

http://en.wikipedia.org/wiki/Experimental_philosophy

~~ Paul
 
Max_B said:
The realist, deterministic view of classical physics is/was absolutely wrong. QM generalised classic physics, so agrees with it in many areas, but QM also explains many things that classical physics cannot. Classical physics died in the first half of 20th Century, replaced by QM. Physics today is about using past observations to probabilistically predict future observations.
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Here's what I said: "Classical physics is not wrong it's only not the whole story." I'm going to link to this wonderful essay by the "late great Isaac Asimov", it explains why I'm right and you are wrong. I found this essay by keyword searching, Is classical physics wrong? Read on.
The Relativity of Wrong
By Isaac Asimov
I RECEIVED a letter the other day. It was handwritten in crabbed penmanship so that it was very difficult to read. Nevertheless, I tried to make it out just in case it might prove to be important. In the first sentence, the writer told me he was majoring in English literature, but felt he needed to teach me science. (I sighed a bit, for I knew very few English Lit majors who are equipped to teach me science, but I am very aware of the vast state of my ignorance and I am prepared to learn as much as I can from anyone, so I read on.)

It seemed that in one of my innumerable essays, I had expressed a certain gladness at living in a century in which we finally got the basis of the universe straight.

I didn't go into detail in the matter, but what I meant was that we now know the basic rules governing the universe, together with the gravitational interrelationships of its gross components, as shown in the theory of relativity worked out between 1905 and 1916. We also know the basic rules governing the subatomic particles and their interrelationships, since these are very neatly described by the quantum theory worked out between 1900 and 1930. What's more, we have found that the galaxies and clusters of galaxies are the basic units of the physical universe, as discovered between 1920 and 1930.

These are all twentieth-century discoveries, you see.

The young specialist in English Lit, having quoted me, went on to lecture me severely on the fact that in every century people have thought they understood the universe at last, and in every century they were proved to be wrong. It follows that the one thing we can say about our modern "knowledge" is that it is wrong. The young man then quoted with approval what Socrates had said on learning that the Delphic oracle had proclaimed him the wisest man in Greece. "If I am the wisest man," said Socrates, "it is because I alone know that I know nothing." the implication was that I was very foolish because I was under the impression I knew a great deal.

My answer to him was, "John, when people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together."

The basic trouble, you see, is that people think that "right" and "wrong" are absolute; that everything that isn't perfectly and completely right is totally and equally wrong.

However, I don't think that's so. It seems to me that right and wrong are fuzzy concepts, and I will devote this essay to an explanation of why I think so.
When my friend the English literature expert tells me that in every century scientists think they have worked out the universe and are always wrong, what I want to know is how wrong are they? Are they always wrong to the same degree? Let's take an example.

In the early days of civilization, the general feeling was that the earth was flat. This was not because people were stupid, or because they were intent on believing silly things. They felt it was flat on the basis of sound evidence. It was not just a matter of "That's how it looks," because the earth does not look flat. It looks chaotically bumpy, with hills, valleys, ravines, cliffs, and so on.

Of course there are plains where, over limited areas, the earth's surface does look fairly flat. One of those plains is in the Tigris-Euphrates area, where the first historical civilization (one with writing) developed, that of the Sumerians.

Perhaps it was the appearance of the plain that persuaded the clever Sumerians to accept the generalization that the earth was flat; that if you somehow evened out all the elevations and depressions, you would be left with flatness. Contributing to the notion may have been the fact that stretches of water (ponds and lakes) looked pretty flat on quiet days.

Another way of looking at it is to ask what is the "curvature" of the earth's surface Over a considerable length, how much does the surface deviate (on the average) from perfect flatness. The flat-earth theory would make it seem that the surface doesn't deviate from flatness at all, that its curvature is 0 to the mile.

Nowadays, of course, we are taught that the flat-earth theory is wrong; that it is all wrong, terribly wrong, absolutely. But it isn't. The curvature of the earth is nearly 0 per mile, so that although the flat-earth theory is wrong, it happens to be nearly right. That's why the theory lasted so long.

There were reasons, to be sure, to find the flat-earth theory unsatisfactory and, about 350 B.C., the Greek philosopher Aristotle summarized them. First, certain stars disappeared beyond the Southern Hemisphere as one traveled north, and beyond the Northern Hemisphere as one traveled south. Second, the earth's shadow on the moon during a lunar eclipse was always the arc of a circle. Third, here on the earth itself, ships disappeared beyond the horizon hull-first in whatever direction they were traveling.

All three observations could not be reasonably explained if the earth's surface were flat, but could be explained by assuming the earth to be a sphere.
Read more: http://chem.tufts.edu/answersinscience/relativityofwrong.htm
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You will see, I chose my wording carefully.
 
Nassim said:
See above.
No scientific knowledge , theories , models...can be proved to be "true" , ever , as Popper used to say.
Science is not about the "truth" either, whatever the latter might be indeed.
Even the highly successful ever quantum theory can turn out to be approximately correct and fundamentally false too, in its turn , like classical physics was/is ...
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I could very well be wrong about this, but it seems you are highly uncomfortable with the provisional status of scientific knowledge and would prefer absolutes.
 
evets010 said:
Here's what I said: "Classical physics is not wrong it's only not the whole story." I'm going to link to this wonderful essay by the "late great Isaac Asimov", it explains why I'm right and you are wrong. I found this essay by keyword searching, Is classical physics wrong? Read on.

You will see, I chose my wording carefully.
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The realist, deterministic view of classical physics is/was absolutely wrong.
 
politicaljunkie said:
To be pedantic, there are deterministic interpretations of QM. Bohm certainly came up with some, the multiverse theory is also another way to bring back determinism
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Max_B said:
But they don't work... the former can't calculate probabilities of the initial particle state... and the latter, well it doesn't calculate probabilities at all (much use that is for predicting a future state). Determinism will tell you unambiguously whether something will/will not happen, where as QM (Copenhagen) can only tell you some probability between will/will not. Many worlds does neither... what use is it...?
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AFAIK, all the interpretations use the same math and make the same predictions, and thus can't be distinguished experimentally (at least so far). There is some disagreement as to whether Bohm is an interpretation or a distinct theory. The probabilities in MWI relate to the likelihood of "landing in" one particular (deterministic) world or another.

Pat
 
Paul C. Anagnostopoulos said:
An arbitrary number of alternate histories of the universe.
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Ah ok. The thing with the partial world interpretation that confuses me is, say we take the double slit experiment. I imagine you are familiar with it - since it is a simple QM experiment and seminal to the observer problem. Assuming alternate histories of the universe, when does the split actually occur in the double slit experiment? Is the split an arbitrary event - if not arbitrary, what causes it? You may know more about this than me as I am not as familiar with the Partial World's interpretation as I am with the Copenhagen interpretation.

My Best,
Bertha
 
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wpb said:
For one thing, it's easy to imagine a quantum wavefunction ("probability wave") as a physical thing, propagating through space. Not so much with a matrix math operation.

Pat
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I don't think the function propagates through space. It remains where it always is, in the texts written by physicists, or in our imagination as we try to explain or understand. What propagates through space is more like mass or energy. The wave function isn't an actual thing. It is only our way of describing what happens.
 
fls said:
I liked that. I've always wondered who convinced physicists that an interpretation is needed. :)
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I think it's just human nature to seek deeper levels of explanation.

IMO, inquiry can be roughly divided into three categories: what, how and why. "Shut up and calculate" stops at "what". QM interpretations attempt to address "how". Metaphysics/philosophy attempts to address "why". (I don't think the categories are necessarily hard-edged; there can be some overlap).

Pat
 
Bertha Huse said:
Assuming alternate histories of the universe, when does the split actually occur in the double slit experiment?
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Here's a far-out speculation (not original with me): The split occurs when the particle "chooses" to go through the left slit or the right slit. So we have two worlds, one where the particle went left and one where it went right. The interference pattern is caused by the interference between the two worlds. If, in our world, the particle went through the left slit, it interferes with the "ghost" particle from the other world, which went through the right slit.

Pat
 
wpb said:
AFAIK, all the interpretations use the same math and make the same predictions, and thus can't be distinguished experimentally (at least so far). There is some disagreement as to whether Bohm is an interpretation or a distinct theory. The probabilities in MWI relate to the likelihood of "landing in" one particular (deterministic) world or another.

Pat
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Rubbish... MWI can't derive the Born rule (probability) from something deeper. All current attempts to fix this are just circular arguments. What I said earlier regarding MWI and probabilities still stands.
 
On the subject of QM, Steve. That article basically said nothing about quantum mechanics, save for a few sentences. Indeed, I don't see how it proves you are right. Secondly, if we are going to start using arguments from authority, then I will quote a current quantum physicist, Vlatko Vedral.

Vlatko Vedral said:
The impression that quantum mechanics is limited to the microworld permeates the public understanding of science. For instance, Columbia University physicist Brian Greene writes on the first page of his hugely successful (and otherwise excellent) book The Elegant Universe that quantum mechanics “provides a theoretical framework for understanding the universe on the smallest of scales.” Classical physics, which comprises any theory that is not quantum, including Albert Einstein’s theories of relativity, handles the largest of scales. Yet this convenient partitioning of the world is a myth. Few modern physicists think that classical physics has equal status with quantum mechanics; it is but a useful approximation of a world that is quantum at all scales. Although quantum effects may be harder to see in the macroworld, the reason has nothing to do with size per se but with the way that quantum systems interact with one another. Until the past decade, experimentalists had not confirmed that quantum behavior persists on a macroscopic scale. Today, however, they routinely do. These effects are more pervasive than anyone ever suspected. They may operate in the cells of our body. Even those of us who make a career of studying these effects have yet to assimilate what they are telling us about the workings of nature. Quantum behavior eludes visualization and common sense. It forces us to rethink how we look at the universe and accept a new and unfamiliar picture of our world
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http://phy.ntnu.edu.tw/~chchang/Notes10b/0611038.pdf
 
politicaljunkie said:
On the subject of QM, Steve. That article basically said nothing about quantum mechanics, save for a few sentences. Indeed, I don't see how it proves you are right. Secondly, if we are going to start using arguments from authority, then I will quote a current quantum physicist, Vlatko Vedral.



http://phy.ntnu.edu.tw/~chchang/Notes10b/0611038.pdf
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Should also add here that the main reason why we don't see every day quantum effects is the human body and its very limited spectrum of perceiving capabilities simply cannot see QM effects in action. Just like the eye does not normally see something like 99% of the electromagnetic wave spectrum.

My Best,
Bertha
 
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