How can we be sure?

would the breaking of your car window by a thief , of which you and nobody else heard at night , take away the reality in the morning your window is broken ......>>

No, because the result of every action is real, see it, hear it, feel it, read it, smell it.

would the breaking of your car window by a thief , of which you and nobody else heard at night , take away the reality in the morning your window is broken ......

I wouldn't be sure until I saw it for myself

yet the window is broken even if nobody saw the break , ever

by the way the thief would know that the window was broken

We only have your word for it, no evidence, no collaboration, just subjective perception.

by telling eachother the Truth. TROLL.

The truth as we know it or a lie disguised as truth?

so does the Universe revolve around you and you only rick ?

Yes, because the perturbation will eventually reach you. How else would you explain your asking that question. You got hit.

The philosophical point here is that there is no way to know for sure that there will be a sound, without observing the event. Just because trees that have fallen in the past have made sounds, it doesn't mean this particular tree will make one, and therefore we cannot know to complete certainty whether the tree will make a sound or not.

According to quantum uncertainty, because no one is there to hear the sound, there is a probability of the tree making the sound, and there's a probability of it not making any sound - since there is no observation, both probabilities exist, and so the statement, 'the tree made a sound' is at a true-false superposition. The tree makes a sound and stays silent at the same time, unless observed and proven otherwise.

If you were to get a tape recorder and record the event, listening to the tape after the event would collapse the wave function, destroying the probabilities and force the tree to have either made a sound or to have stayed silent. And then you would know for sure because you would have observed the event.

If you observe an event, it's either one or another. If you do not observe a random event, it's both until you observe it. That's why we cannot be sure about anything unless we observe it.

And to answer the question, according to my explanation of the scenario, the tree makes a sound and stays silent simultaneously. And that's according to the uncertainty principle. So, science doesn't necessarily say that the tree makes a sound. Uncertainty principle is a scientific explanation of the philosophical viewpoint of this scenario.

As for practicality, if we knew a tree had fallen in the woods, we would of course say it has made a sound. That's because due to our prior experience with falling trees, we would say that the probability of it making a sound is a lot higher than it staying silent. However, since correlation doesn't imply causality, we can't be sure of anything unless it's observed.

The goal of this question isn't to actually tempt us to figure out whether trees make sounds when the fall. It's really just to make us think about how we can sure about anything. Which we can't. Unless it's observed.

Just my 2 cents.

Regarding Quantum superposition you ought to think on how they know the difference after observing a collapse, when if taken as they explain, the alternative was not observed...it just may be the case that "observation" is a poorly understood word in the physics realm...in the least, it certainly seems poorly explained to me...

A superposition, as I understand it, cannot be observed, as interacting with it will cause it to collapse into a definite state. A superposition is a wave of potential. It can collapse into many different definite states, but while it still is a superposition it is all of those states simultaneously, and none of them. It is not possible to predict precisely which definite state it will be, but it is possible to calculate probabilities. Measuring or observing it will collapse it.

The way I break this down in my own understanding is that if two quantum waves of superposition interact, the interaction will cause something to happen. There is some kind of "observer effect" that facilitates a collapse into one of the many definite states. This is how I envision reality coming about. A whole lot of undefined, superpositioned potential reality that forms series of events, and in this process particles and waves are shaped and molded by means of a negotiation between them, into what reality is at any given time.
These superpositions contain everything that can possibly exist, and that includes not only the components of physical objects, but also the components of consciousness. That is why I maintain my belief that consciousness is fundamental to reality, not some fluke product of it. In the same way that repeated and ongoing collapses of superpositions cause the physical universe to happen and eventually reach the complexities it currently has, these superpositions have progressed similarly as conscious expressions, until the phenomenon known as 'humans' are a reality.

...actually you aim to observe phenomena while in a quantum superposition from where supposedly you provoke the collapse...but bare in mind that scientists use the terminology "observe" as meaning measurement, the process is done by machines, if I am not wrong in judgement, they do it by using using particle bombardment, thus it works but not directly by looking at it, as I am sure you well know...after all electronic microscopes are not lenses...so interference from the techniques in use may well come to explain the odd behaviour we see... the thing is, for instance in the double slit experiment, the difference from having a two stripes result from incoming photons at the end or having several stripes must always be observed or detected in order to be compared...I guess what they mean is that in the case when you get several stripes, observation is done after particles arrive at the end, while when you get two stripes observation is done near the slits on which the particles are going through...I strongly suspect of some sort of interference done by the apparatus used to make this measurements, the so called"observations"... probably they affect the pilot wave or the field which guides the particle...new interpretation are going back to the original idea that a particle and a guiding wave are both in place instead of just having either a particle or a wave...

I do not think the equipment used is the explanation for the odd behavior. I am not a quantum physicist, so I could be wrong, of course, but blaming the equipment just seems a little too simple, in my opinion. Besides, some of the oddities are mathematically explained with ideas like the uncertainty principle.
Understanding this is not easy for me. What little success I feel I've had has come from discarding some old notions that I held fundamental to my view of reality. It is important to note that even though quantum physics describes the very same phenomena that classical physics describes, the rules of classical physics do not necessarily apply. Concepts such as a fixed location in space and a linear time progression are not applicable to all quantum phenomena. There are quantum entities that have no location, and changes that affect things in multiple directions of time.

By the way Fil, I find it interesting to speak with you now that we have managed to put aside the hostility. I don't know what changed, but I am glad it did.

My "hostility" was never against you as a person as in any post it is not against anyone...for all that I know you JL or even Fresco can be the most charming chaps...my "hostility", my outbursts, are essentially a physical reaction to the unwillingness on clarifying...and thus mainly directed against a very specific attitude, that probably in many cases, comes about on an unconscious level...you see my natural and vital aim in philosophy is precisely understanding with precision, as from where I stand there is no other way of incorporating knowledge about anything...I also dislike the permanent portray of currents of thought when against open inquiry in all directions...those who are familiar with me know better that most of my "spiced up" posts, on the momentum, do carry more semantic poetry then harmful intention...

Regarding Quantum phenomena lack of sufficient information on logical and mechanical links is a perfect example of something that wrecks my nerves...nevertheless I am honestly trying to be more patient while all the way keep on pushing people to think further by questioning previous assumptions...honestly hope we can debate our differences in a more constructive manner...

Quantum physics may not lack sufficient information on logical and mechanical links. It may be that our preconditioning makes us superimpose our logic derived from classical physics on to quantum phenomena.

...entanglement is a perfect example of quantum weirdness, nobody knows how it works...so far was best described for Einstein as "spooky action at a distance"...

As I understand it, wave-particle duality is central to the issue.

http://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality

It is kind of mind boggling, but I find it interesting, mostly on a metaphysical level. As we uncover more about the world of quantum physics, it is not unlikely that our understanding of what reality is might change drastically. Such change is slow, but if I am to indulge in speculations about the future, I think it may lead us to understand that classical physics is more about reality as it appears to humans. It's about us. Not that this would make it any less real. That's kind of the way with changes like these. Suddenly everything's different, and yet nothing's changed...

well think of the wave -particle duality as a wave on the ocean , at first the wave is a coherent structure , but as the top of the wave becomes a crest and falls down it foams and becomes particles of water , yet for the most part the wave is still intact

Which truth, perceptive, philosophic, or practical?

Takes a troll to know a troll -- whatever that means -- p, p, or p