Solution: http://dictionary.reference.com/search?q=sound defines "sound" as, "Vibrations transmitted through an elastic solid or a liquid or gas, with frequencies in the approximate range of 20 to 20,000 hertz, capable of being detected by human organs of hearing." Since sound only needs to be capable of being detected by human organs of hearing, and since a falling tree will transmit vibrations through a gas (specifically, air), with frequencies in the approximate range of 20 to 20,000 hertz, then the answer is, yes.

QED:

Not a lot more I can say other than "I agree."

Of cause It does, thats like saying your TV turns off everytime you go away, which would be very useful for saving electricity, but unfortunately a motion sensor cannot be built into a tree

so are you saying supersonic and subsonic sound don't exist? they surely can't be heard by humans

Sound is a function of the ears though, this is the flaw in your argument. Does it make a sound? No, not with nothing around to pick up the vibrations. Without the ear, and I don't only mean the human ear, I mean all things with ears, it is only a vibration.

We can set up microphones, but the sound they transmit to our ears is a product of the microphone, the recording equipment and the speakers. It is not the tree.

The point of this question is to show that some things that seem to simple to answer are not. You need to remember that empirically, to the human, without hearing the tree fall, it does not make a sound, even though it does push energy out in the form of vibrations and pressure changes.

So the answer is no, there is no sound.

Also, think about deaf people. Do you ask them if they hear the sound? They feel vibrations, yes, but they do not hear sound without the ear. The inclusion of the functional ear is crucial for there to be sound.

does this apply to taste, smell, touch or vision?

I really can't see where you are coming from

Jesus H. Christ! Ok, I'll revise my answer to any sound any living thing can hear.

Mu

Sound is created by the action of the tree falling.....whether someone is standing close by with a set of ear drums is irrelevant.

I wasn't there, i dunno

Yes it does. why would it not?

Ok, if you fart in an elevator and there's no one around to smell it, does it stink?

Sound is simply the way a brain is designed to interpret varying frequencies and amplitudes of vibrations. No brain, no sound, simple as that.

That depends on whether you find your flatulence to be of pleasing aroma or not. However it still does smell since YOU are around with (presumably) functional olfactory sense to sense it.

But does it have to be a human brain?

In my mind no. I think about the question assuming that "no one" means no conscious creature with a brain and ears (or variations of ears). Obviously this is an assumption and I know it could never happen in a real world scenario but we need to assume certain things to have a concrete answer to a question like this.

I agree that if there are no living things capable of detecting sound waves then the question is moot because there's no one around to care whether or not it made a sound. But the sound waves would still be created. The potential for sound to be heard would still be there.

I asked my 5 y/o nephew. Here's his reply:

"NO silly, trees don't talk! That's just on TV."

I gave you a point for good old common sense!

I agree and understand your point. I suppose the essence of my argument is that Potential for sound does not imply sound. Sound waves are natural and unavoidable in this situation. They only become what we understand as sound when they enter a functioning ear.

"Sound is a function of the ears though"

Wrong. Sound is a wave that is caused by the back and forth movements of the medium it is traveling in. The waves of sound signify changes in air pressure; the presence of sensory organs has NOTHING to do with the existence of sound. The human ear just responds to a spectrum of frequencies it can detect, much like our eyes are tuned to register a small portion of the electromagnetic spectrum. Do you content that infrared waves don't exist because they can't be detected by our eyes? No, unless you modify the definition of "light" to "radiation that is only perceptible to human eyes". Same deal with sound. And even if you were to make a modification to the question and have it say, "does it make an AUDIBLE sound," you still wouldn't have a case because the frequency range would still be within that 20Hz - 20kHz range detectable by the human ear. Subjective perception or the lack thereof does not affect the answer one way or another. It's almost as absurd as saying if a nuclear bomb were to be detonated on Venus and we didn't see it, it technically (by your logic) would not have emitted any light.

"to the human, without hearing the tree fall, it does not make a sound, even though it does push energy out in the form of vibrations and pressure changes."

You're assuming ears or sensory equipment are necessary for sound to technically exist, which is wholly inaccurate. Scientifically, sound is an instantaneous change in air pressure caused by vibrating particles, whether or not something is present to sense it or not. If you want to argue philosophy, this is not a discussion to argue it in, because science refutes your argument from the get go.

http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/sound/u11l1c.html

"No brain, no sound, simple as that."

http://stason.org/TULARC/physics/acoustics-faq/2-1-What-is-sound.html

http://www.cartage.org.lb/en/themes/Sciences/Physics/Acoustics/PropertiesSound/PropertiesSound.htm

http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/sound/u11l1c.html

Scientifically, sound is an instantaneous and periodic change in air pressure caused by vibrating particles in a medium. Sound exists whether or not a brain and sensory organs are there to detect and register it. Going back to the light example: since our brains cannot register infrared or ultraviolet light waves, does that mean those waves don't exist? Absolutely not; in fact that's an absurd position to take. So how is saying sound doesn't exist because there's nothing to detect it and store it as sensory information, any more sensible?

You're not getting it.

Light is to Vibration as Sight is to Sound.

Light is there no matter what, even without the eye, and it is detectable through other means than the eye. Vibrations can be traces with machines as well, and we can identify both without the inclusion of our relative senses.

It is not the same though. If you pick up vibrations via a machine that is meant to do so, and have it display wave lengths on a display without playing the amplified sound, even though the machine tells you that there are vibrations, you do not get the experience of hearing it. Sound is that experience. Where vibration is interpreted by the mind via the ear.

Hell, you may even point at the display in front of you that is showing the wave lengths and everyone would agree that what you're pointing at is a representation of sound, because it's so easy to just call it a sound and everyone know what you're talking about, but it's not sound.

Look at it this way. Vibration and Sound are different words. What is the difference? ONE YOU HEAR, the other you don't necessarily have to hear.

Science stems from philosophy my friend. Remember that the greatest tool that we have is the mind, and not the tools that the mind uses. Use reason before your science book.

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

Also, if still you don't get it, give up. There's no good way to explain this (or anything) to someone that doesn't want to learn... and I am already aware of everything that you've had to say.

oh no ! this was a question from the Theory of Knowledge class at my school !! ];

I am not saying that sound waves and vibrations are not created. They certainly are, whether we can perceive them or not. However, different beings can interpret the same sound waves differently; sound is not a constant. In my mind this proves that "sound" is only a label for the way we perceive any given sound wave. There is a flaw in your example about infrared or ultraviolet waves. We know these waves exist just like we know the sound waves exist. Human anatomy does not have any sensory organs for registering these waves so they are not a fair comparison. Again, the I am not debating the existence of sound waves, only the point at which they become what we recognize as "sound".