A quantum experiment by Feynman:

Originally posted by PinkFloyd
This question has always intrigued me. And I always find myself changing which side I'm on I do have a question though: Why doesn't the same theory apply to the other senses as well. If a star goes nova, we don't see the results until the light travels millions of light years to get to us, right? But none of us were around to see it, when it occurred ...[text shortened]... n't "disturbed until millions of years later, when there were optic nerves to witness it?

It does apply to other senses. However it's important to remember that just because you didn't see or hear something that doesn't mean nothing happened. The branch breaking in the forest when transcribed to sight doesn't become "does the tree exist", it becomes "does what looks like a tree exist".

Originally posted by forkedknight
The "waveform collapses when observed" thing comes form the fact that even if only ONE electron is sent though the double slits, it produces a wave pattern.

How does a single electron produce a wave patten? That's why they try to observe which slit it passes through, but once they've done that, there is no longer a wave pattern.

I don't think one electron produces a wave pattern. By wave pattern you mean the pattern on the detector screen right?

The light was "disturbed" but not yet detected and interpreted as a visual image.

These two are just arguing about the "proper" definition of a word. Vibrations in the air are interpreted by the ear and brain as a sound sensation. The intensity and wavelength of light is interpreted by the eye as image sensations. It's the same thing.

Originally posted by Wheely
I disagree. Sound is a construct of your head. Air being disturbed is just that, air being disturbed. If you were deaf air could be disturbed as much as you like but you´d hear no sound.

Here you are obviously talking about the perception of sound -right?

In every day English, when somebody like me talks about sound and who understands the chain of physic events which leads to the perception of sound, I think that, like me, they are usually not talking about the perception of sound but sound as a physical disturbance in the air which is independent of anyone hearing it.

Originally posted by Andrew Hamilton
Here you are obviously talking about the perception of sound -right?

In every day English, when somebody like me talks about sound and who understands the chain of physic events which leads to the perception of sound, I think that, like me, they are usually not talking about the perception of sound but sound as a physical disturbance in the air which is independent of anyone hearing it.

Yes. For me, the perception of sound is the sound. The physical event is a potential for sound.

Unfortunately these differences in semantics make the branch breaking in a forest question far less interesting.

Originally posted by AThousandYoung
The light was "disturbed" but not yet detected and interpreted as a visual image.

These two are just arguing about the "proper" definition of a word. Vibrations in the air are interpreted by the ear and brain as a sound sensation. The intensity and wavelength of light is interpreted by the eye as image sensations. It's the same thing.

You are correct but I find the second one rather intriguing. We tend to think we know the world because we can see it (well, most of us can). Seeing, however, happens in your own head, not out in the real world.

Originally posted by Wheely
I disagree. Sound is a construct of your head. Air being disturbed is just that, air being disturbed. If you were deaf air could be disturbed as much as you like but you´d hear no sound.

That is totally not true. Did you know there are football (american style) teams composed of totally deaf people? Do you know how they get the starting and stopping signals? In regular games, they use a whistle.
With deaf people who cannot hear such sounds, they use those big bass drums of the marching bands. A big whack on those drums sends a big sound wave that is not heard but FELT in the chest, they are trained to feel that and when they do they start or stop. You don't have to hear sound to feel the effects of it. Another thing, when you have a bass speaker pumping out the sounds of the bass instruments, when you put your hand near it you don't have to hear it, you can feel the air swooshing back and forth right on your hand. A deaf person would not hear the sound but would certainly feel the rush of air vibrations.

Originally posted by sonhouse
That is totally not true. Did you know there are football (american style) teams composed of totally deaf people? Do you know how they get the starting and stopping signals? In regular games, they use a whistle.
With deaf people who cannot hear such sounds, they use those big bass drums of the marching bands. A big whack on those drums sends a big sound wa ...[text shortened]... d. A deaf person would not hear the sound but would certainly feel the rush of air vibrations.

Sorry but I don't see the relevance. We are talking about sounds, not alternative ways of interpreting air movement. I fully appreciate that people can feel vibrations.

Originally posted by Wheely
Sorry but I don't see the relevance. We are talking about sounds, not alternative ways of interpreting air movement. I fully appreciate that people can feel vibrations.

You are just debating the definition of the word "sound".

Everyone seems to be in agreement that if the tree falls when nobody is around that a pressure wave travels through the air. Everyone seems to be in agreement that this pressure wave is independent of any listener and happens weather or not anyone is around to hear it.

Therefore the only question that is being debated here is "is this pressure wave "sound" or does the pressure wave need to be heard in order for it to be "sound" ".

The answer is that the pressure wave is sound. If nobody perceives the sound, because nobody is around to hear it, it is still a sound. Sound does not need be heard to be sound, the notion that pressure waves become sound if we are in range to listen to them is silly.

There is perhaps a better argument for reasoning that pressure waves that are outside the human audio range (and thus can never be heard) are not "sound". But again this is simply debating the definition of the word "sound", the behavior of the system is not influenced at all by our definitions of how we describe it.

Originally posted by Wheely
Sorry but I don't see the relevance. We are talking about sounds, not alternative ways of interpreting air movement. I fully appreciate that people can feel vibrations.

It goes to the heart of what we call sound, which is what the brain interprets in the vibrations inherent in the air. The fact that a deaf person does not hear directly and the fact that even that same deaf person can feel the sound means both ways of perceiving this energy is inherently equal.
The only difference is getting subtle modulations that we, the non deaf, would perceive as vocalizations or music or sounds of cars crashing, etc.
There is no doubt hearing enabled ones can extract volumes of information forever denied the deaf, nonetheless, they can still perceive the percussion of sounds and that goes to the heart of that old conundrum about nobody in a forest. A person, modern intelligent person, feeling the vibrations of sounds even if deaf, is AWARE of the vibrations, that is the heart of it IMHO.

Originally posted by MattP
You are just debating the definition of the word "sound".

I have come to realise this.

You choose to call it a particular frequency of air movement. I choose to call it the thing in your head.

I don´t really see the distinction between air movement you can hear and that you can, particularly as it is different for different people (and animals). I suspect, if evolution hadn´t given us ears, we wouldn´t have a word for sound.

Still, it is a rather pointless discussion really when, as you say, everyone pretty much agrees anyway.

Originally posted by Wheely
I have come to realise this.

You choose to call it a particular frequency of air movement. I choose to call it the thing in your head.

I don´t really see the distinction between air movement you can hear and that you can, particularly as it is different for different people (and animals). I suspect, if evolution hadn´t given us ears, we wouldn´t have ...[text shortened]... it is a rather pointless discussion really when, as you say, everyone pretty much agrees anyway.

You would have to come to the conclusion it would not be sound if say, you had a symphony orchestra of mindless robots who can be programmed to be virtuoso's on whatever instrument they play and so 50 or 60 of them playing together with a mindless robot conductor and they start playing but they are in the middle of a desert with no people around, they they would not be generating sound, right?

Think about the definition of sound and this:
http://www.sciencedaily.com/releases/2008/07/080717140435.htm

Originally posted by Andrew Hamilton
[b]I have always been very suspicious one of the main interpretations of quantum physics that basically says something does not “exist” unless it is “observed” (and therefore there is no objective reality!)

This so called 'main interpretation is incorrect. What quantum theorists have said is, for example:

Electrons passing through this apparatus, in so far as we are able to fathom the matter, do not take route h and do not take route s and do not take both of these routes and do not take neither of these routes; and the trouble is that those four possibilities are simply all of the logical possibilities…[i]


- David Z Albert (twentieth century physicist)

Which corresponds with:


It’s character is neither existent, nor non-existent,
Nor both existent and non-existent, nor neither.
Centrists should know true reality
That is free from these four possibilities.[ii]

- Buddhist understanding of reality.

One problem with the objective reality bit, not real unless it's observed, what about when there was no life forms anywhere in our universe, say when it was a couple of years old. There were for sure nobody to observe it but I get the feeling the universe didn't give a crap if an intelligence was looking or not, it just kept on doing it's thing, expanding, cooling off, etc.