Causality and Quantum mechanics

Factual Questions
21

[QUOTE=Exapno Mapcase]
voodoonirvana, if you don’t understand basic physics terminology your opponent will be able to say anything, including nonsense, and you will not be able to dispute it. You should stay out of all arguments in which you don’t know the base jargon of the field. You will lose every time.
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Did I not explain this to you sufficiently?

[QUOTE=Exapno Mapcase]
This is as true as Newtonian physics. I.e., it’ll work for any argument you ever get in while dwelling in the macroworld. :slight_smile:
[/QUOTE]

Do you get off on being a wise ass?

22

[QUOTE=Exapno Mapcase]

voodoonirvana, if you don’t understand basic physics terminology your opponent will be able to say anything, including nonsense, and you will not be able to dispute it. You should stay out of all arguments in which you don’t know the base jargon of the field. You will lose every time.
[/QUOTE]

What reason could you possibly have for repeating this? You already said the same thing earlier in the thread. The only thing I can come up with is that you want to put me down because my retort to you possibly bruised your ego. I hope it made you feel better.

23

[QUOTE=Exapno Mapcase]
And non-existence is no doubt a species of existence.

Forget the wordplay…
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No, you’ve misunderstood me. I don’t mean the word “retrocausality” “sounds” like it would refer to a species of causality. I mean that retrocausality, as you have described it, seems like a species of causality to me. (What do I mean by “species of causality?” Just that its an example of causality.)

So my question should be construed as follows: What is it about retrocausality which makes it not eligible to count as an example of causality simpliciter?

It seemed like you were saying it’s not causality because it involves something which, were we to describe it in causal terms, we would have to describe as involving effects preceding their causes. Yet, I don’t think it’s necessary to the concept of causality that examples of it must procede “forward” in time. But am I wrong about that?

-FrL-

24

[QUOTE=Exapno Mapcase]

voodoonirvana, if you don’t understand basic physics terminology your opponent will be able to say anything, including nonsense, and you will not be able to dispute it. You should stay out of all arguments in which you don’t know the base jargon of the field. You will lose every time.

[/QUOTE]

I don’t think this is true. Persistant questioning of a bullshitter will generally reveal a bullshitter to be a bullshitter on purely logical grounds. :stuck_out_tongue:

-FrL-

25

[QUOTE=Chronos]
Causality does exist in quantum mechanics, and it’s just as absolute as it is in the familiar Newtonian physics. But it manifests in a much more subtle way, which is difficult to understand without understanding a lot of other things about quantum mechanics.
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Is this true? I’ve been doing some Googling, and I can’t seem to find anything that clearly says that causality is absolute , or can be thrown out the window at the quantum level, as Exapno Mapcase suggests.

26

[QUOTE=Stranger On A Train]
So, a lack of causality on the probabilistic scale of quantum mechanics does not translate to issues at the stochastically deterministic scale of the macro world.
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Where does the “break” occur between the quantum world and the macro world? What explanation for that dividing line is there? Seems somewhat random and arbitrary. “At this level things behave this way and at a bigger level they behave differently. Why? Just cuz is why.” Why do a collection of atoms behave in a macro sense but not individually? Seems to go to the emergent behavior mentioned earlier but I really have no idea.

I am not arguing with the results of quantum weirdness (technical term). My understanding was that quantum weirdness could indeed present itself in the macro world…at least in theory. The chances that one atom among a bazillion does something seemingly strange is well studied. The chances that every atom in your body (or whatever macro object) does so simultaneously is mind bogglingly slim but not zero.

So, on a macro scale all seems in order but it doesn’t have to be. Does it?

27

[QUOTE=Whack-a-Mole]
The chances that one atom among a bazillion does something seemingly strange is well studied.
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Well, as you can tell by this thread, I’m no expert, but I don’t think it’s one out of a bazillion that acts strange. They ALL act strange.

Check out how electrons behave in the Double-slit experiment as demonstrated in the cartoon linked to below. I’ve got so many questions about this, I may start another thread.

28

[QUOTE=voodoonirvana]
Check out how electrons behave in the Double-slit experiment as demonstrated in the cartoon linked to below. I’ve got so many questions about this, I may start another thread.

[/QUOTE]

Nifty animation. I’ll keep that one.

The double-slit experiment always blew my mind but it seems scientists have an explanation they are content with (although the details are far beyond my reckoning and the whole thing still melts my brain).

If you are interested read this link for a decent layman’s explanation and follow the hyper-links in the article if you want to delve further. If you do not like that just Google “wave particle duality” for loads of info.

29

Thanks. I’ll check it out in the morning.

30

[QUOTE=Whack-a-Mole]
Where does the “break” occur between the quantum world and the macro world? What explanation for that dividing line is there? Seems somewhat random and arbitrary…So, on a macro scale all seems in order but it doesn’t have to be. Does it?
[/QUOTE]
The “dividing line” between quantum mechanical behavior and the macro world is on the scale of individual particles. Electrons, being of relatively low mass, can bebop all around the universe, though they’re most likely to be somewhere in the vicinity of where you expect them to be. Heavier nuclear particles, like protons and neutrons, are “pretty” deterministic, only occasionally escaping on their own, at a rate dependant upon how resistant the particular nuclear configuration is to instability.

Once you get to the level of molecules, quantum effects are reduced to the probability and longevity of electrostatic bonds (ionic, covalent, and hydrogen) and the Van der Waals forces. Since we can model these as effectively deterministic qualities (i.e. chemical kinetics and the law of mass action) we can at that point seperate from the “weirdness” of quantum mechanics, which is a great relief to most physical chemists who wish to have no truck with such nonsense. In the world of complex organic chemistry and biochemistry, the long chains and extensive protein structures are such that the electrostatic forces are sufficiently intense to conceal most problems resulting from a random electron popping off to the pub for a quick one. By the time you bring sufficient quantities of a substance to the table to do anything valuable with them, the stochastic nature of QM is averaged out to a calm, blandly predictable medium, and the chemists (an Antediluvian lot with no interest in Fermi-Dirac statistics or Lie algebra) can resolve all of their problems with nothing more mathematically complex than some very simple linear differential equations.

In short, once you get to quantities of particals sufficient to involve chemical reactions, quantum mechanics (except for some very special and limited circumstances) becomes a nonissue. It’s only when you’re dealing with individual particles, or a group of particles that all acting in concert, that QM effects become manifest. Your everyday chemist or electrical engineer needs not the barest shred of actual knowledge about quantum mechanics, even though it lies beneath all that happens. It’s kind of like Congress, actually, except its more predictable.

Stranger

31

[QUOTE=voodoonirvana]
Check out how electrons behave in the Double-slit experiment as demonstrated in the cartoon linked to below. I’ve got so many questions about this, I may start another thread.
[/QUOTE]
The double slit experiment isn’t all that strange, provided you accept that electrons are not in fact particles in the sense of being “little balls of stuff”, and instead behave in a manner more becoming of waves. (You can perform the double slit experiment with water and get the same interference patterns.) This is less one of the “weirdnesses” of quantum mechanics and more a semantic readjustment. Electrons aren’t “particles” like you think of grains of sand; they’re waveforms with a locus of action. Ditto for all fundamental particles. “Wave-particle duality” is just a way of saying that we don’t have a macro-level concept for what leptons, quarks and gauge bosons actually are.

Stranger

32

[QUOTE=Exapno Mapcase]
I don’t mean to be snarky either, but if you don’t understand a concept as basic as Newtonian macroscopic world, you should not be involved in any arguments with anybody about quantum causality. Some familiarly with physics is a prerequisite just to be use to talk about the subject.
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That didn’t stop Capra from writing The Tao of Physics and we’ve been suffering the consequences for 30 years now.

33

[QUOTE=Whack-a-Mole]
Where does the “break” occur between the quantum world and the macro world? What explanation for that dividing line is there? Seems somewhat random and arbitrary. “At this level things behave this way and at a bigger level they behave differently. Why? Just cuz is why.”
[/QUOTE]

And this is the biggest hang-up most people, even some young physicists, have with understanding. There is no dividing line. It’s a gradient, with the quantum effects becoming less and less important as we scale up. At our everyday scales we can effectively ignore them.

34

In my mind, I analogize to it a poll question. Go ask 1 person how they will vote. That’s pretty meaningless, the margin of error is essentially infinite. Now go ask 15 people. Can you make predictions from that? Somewhat. Now go ask 1,500 people. Yep, you can start making conclusions from that, with a reasonable margin of error. Now go ask 15,000,000 people. Your conclusion is rock solid. There is some infintesimal chance that you just got very unlucky, but it’s negligible.

In the same way, although there is an infintesimal chance that all the electron is my hand will suddenly move 3 feet to the left, the chance of it is completely negligible.

The weirdness of quantum mechanics dissapears as you move up the scale, because it’s essentially probabilistic, and at the macro- scale we live in, anything you look at involves incredibly large sample sizes.

35

[QUOTE=Mathochist]
That didn’t stop Capra from writing The Tao of Physics and we’ve been suffering the consequences for 30 years now.
[/QUOTE]
Ah yes, New Age Physics. I recommend Alan Sokal and Jean Bricmont’s Fashionable Nonsense: Postmodern Intellectuals’ Abuse of Science as an antidote. There are good philosophical discussions to be had regarding the consequences of quantum mechanics, but not by people whose grasp is limited to making comparisons between Eastern mystical religions and Schrödinger’s Cat.

Stranger

36

According to Brian Greene of The Elegant Universe, at the planck scale, such things as left and right, up and down, back and forth, even before and after, get all jumbled up in the quantum foam. :dubious:

37

Logic deals with cause and effect. What it doesn’t deal with, however, is what the initial cause of all other effects is.

Similar to time - time deals with the movement of matter. It doesn’t deal with the universe before any matter was known to exist.

All the tools we have to examine the universe in its present are completely inapplicable to the universe at its creation, or before.

38

[QUOTE=ReggieB]
Logic deals with cause and effect. What it doesn’t deal with, however, is what the initial cause of all other effects is.
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I’ve never heard of a conception of logic which characterizes it as chiefly concerned with cause and effect. Even given such a conception, your second sentence is difficult to interprete. If logic deals with cause, then if there is a cause of all effects, then logic deals with that cause as well. If logic doesn’t deal with it, then it’s not a cause (or an effect) after all. But if it’s not a cause, then since your characterization of it is “the cause of all other effects” I am left with no way to understand what you might be talking about.

If time deals with the movement of matter, then if matter moved before any matter was known to exist, then time deals and dealt with it. I think what you mean is to say that the notion of time is not relevant to questions about what happens under circumstances in which there is no matter in existence. Hence, if the universe is ever supposed to have been in a state in which there was no matter in it, then it would not make sense to talk about time passing while that state endured. I think it is correct to say there can’t be time where there is no matter (if we understand the term “matter” in the right way, for example, as including energy under its extension) but by the same token it makes no sense to talk, as you try to do, about a time “before” any matter existed.

Why should we admit this but not also say that “All the tools I have to examine those segments of the two thousand mile radius region of space I’ve been able to experience are completely inapplicable to the universe beyond that radius”?

-Kris

39

[QUOTE=Frylock]
I’ve never heard of a conception of logic which characterizes it as chiefly concerned with cause and effect. Even given such a conception, your second sentence is difficult to interprete. If logic deals with cause, then if there is a cause of all effects, then logic deals with that cause as well. If logic doesn’t deal with it, then it’s not a cause (or an effect) after all. But if it’s not a cause, then since your characterization of it is “the cause of all other effects” I am left with no way to understand what you might be talking about.
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For a cause to effectively be examined, there must be a way to find its cause and its effects. A ‘first cause’ has no prior cause, thus logic can only deal with its effects, and not the first cause itself, as there is nothing before it to derive its attributes from. Evolutionary theory has prior species to derive base attributes that can be modified through mutations from. Abiogenesis has prior energy to derive the base attributes of life from. What does energy derive its attributes from? Logic cannot help us answer this question unless we discover something to have existed before energy; then it can be posed as to what that effect was caused by.

You can attempt inductive logic to figure out the attributes of some initial cause…but the chances of you being right, even if you’ve put every last piece of existence into consideration, is less than worthwhile.

This idea is akin to ‘The tao that is named is not the eternal tao’. Nobody can ever know what started it all, as there is nothing before it to set the stage for examination through logic. It’s very much a, ‘Alright, something started this shitheap called existence, but we can never know just what it was’ sort of deal.

[QUOTE=Frylock]
If time deals with the movement of matter, then if matter moved before any matter was known to exist, then time deals and dealt with it. I think what you mean is to say that the notion of time is not relevant to questions about what happens under circumstances in which there is no matter in existence. Hence, if the universe is ever supposed to have been in a state in which there was no matter in it, then it would not make sense to talk about time passing while that state endured. I think it is correct to say there can’t be time where there is no matter (if we understand the term “matter” in the right way, for example, as including energy under its extension) but by the same token it makes no sense to talk, as you try to do, about a time “before” any matter existed.
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It’s not necessarily a ‘time’ before any matter (I use energy and matter synonymously…compressed air is still air) existed; simply a state. And you understood well what I was saying, so I’ll leave this alone.

[QUOTE=Frylock]
Why should we admit this but not also say that “All the tools I have to examine those segments of the two thousand mile radius region of space I’ve been able to experience are completely inapplicable to the universe beyond that radius”?
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Because we can still observe the universe outside of our immediate sphere of existence; we can’t observe it at creation, collect data on it at creation, or make any verifiable conclusions about it at creation (all of these independent of its creation being atheist or theist). Seems sensible to me. However, if you can make an effective argument as to why I should apply logic to a first cause, I’ll throw my thinking out the window.