What does it mean in philosophy and perceptual psychology to ask 'If a tree falls in the forest and no one is around to hear it does it make a sound'?

Answer 1

The question in philosophy and psychology is that while a tree falling "should make" sound, the existence of the sound can depend on its ability to be perceived (now or later). While physics states that a tree falling will create the vibrations we call sound, their existence as sound is only recognized when perceived (heard) and cannot be absolutely postulated unless and until this occurs. This can be extended beyond this example, as far as the metaphysical concepts of existence and perception, e.g. without someone or something there to perceive it, does the tree even exist at all?

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The philosophical and perceptual psychological background about this question:

Philosopher George Berkeley wrote A Treatise Concerning the Principles of Human Knowledge (1710). He wrote, in part, "But, say you, surely there is nothing easier than for me to imagine trees, for instance, in a park [...] and nobody by to perceive them. [...] The objects of sense exist only when they are perceived; the trees therefore are in the garden [...] no longer than while there is somebody by to perceive them."

"The objects of sense..." refers to objects or events that we perceive with the 5 senses--hearing, sight, smell, taste, touch. However, as a philosophy question, raises the issue of perception in philosophy: Does something still exist if we cannot perceive it with one of our senses. And, just what do we perceive...

For twenty-years after Berkeley's writing, philosophers took up " consideration of the emergence of meaning" (quote from Wikipedia). In 1754, William Fossett paraphrased Berkeley's writing in Fossett's writing, Natural States. However, it should be noted neither of these philosophers actually stated the quote in question ("If a tree falls in a forest and no one is around to hear it, does it make a sound").

Over 100 years later, in June 1883, a question was posed in The Chautauquan magazine, "If a tree were to fall on an island where there were no human beings would there be any sound." [Italics added].

This idea in 1700s-1800s was seminal work about the idea of perception. It has lead to a host of similarly phrased questions posed to students, first in Universities to philosophy and psychology students, and then to high school students.
The point is to generate thinking about problems of perception.

Some similarly stated questions include:

1. If a tree falls in the forest... [some people add other details here such as distance away] but no one HEARS it...does it make a sound.
2. If a leaf falls in the forest but no one is present to SEE it, does the leaf still fall, gathering with other leaves on the forest floor.
3. If you SMELL the strong fragrance of aftershave, but you see no one nearby, do you assume a man just passed by before you arrived there?
4. If you experience the distinctive TASTE of onions in a casserole but did not see anyone make or bake the food, can you be certain the cook added fresh onions to it.
5. If you put your hand into a hole in a closed box and you TOUCH something that feels cold and wet, can you assume it came from a block of ice.
6. (You can probably think of more of your own 'If'-perception questions.)

In each question, it seeks to make us aware of how perception affects how we interpret and assign meaning to ordinary events and experiences--or, to experimental experiences scientists or researchers create for us. It asks us to consider events and meanings of events, even if we personally do not witness or experience them, e.g.

• The tree no one heard still thudded; the leaf still detached from the tree without requiring our sight; aftershave is typically associated with men, even if we missed seeing the man pass by; the food might have contained onion salt versus chopped onions; and lastly, everything that is 'cold and wet' is not ice.
• Likewise, Blacks and women endured years of oppression... Events halfway around the world, like wars, take place even if we don't see the fighting.... Nazis killed millions of Jews in the Holocaust... Babies and children still die of starvation in some countries... etc.

A year after The Chautauquan magazine posited the question, magazine Scientific American took up the ongoing [until then strictly philosophical] debate in 1884, providing a science explanation for sound, ""Sound is vibration, transmitted to our senses through the mechanism of the ear, and recognized as sound only at our nerve centers. The falling of the tree or any other disturbance will produce vibration of the air. If there be no ears to hear, there will be no sound." (Scientific American).

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Below, other contributors take up various positions, including strictly scientific points of view.

Related Response to the above:
This is a philosophy question. Yes, events happen even though we are not paying attention. This is speaking straight logic. However, it may just depend on the individual's concept of reality.


A Question About Evidence
How do we know said tree fell if no one was around to witness it, or even hear it? It's a philosophical question, so it does puzzle the mind. It's like exercise for the mind: the more you use it the stronger it gets.


Another answer that attempts to bridge perception with science:

Although this question is often restated as a crude satire, "If Helen Keller fell over in a forest would there be any noise?", the answer stays the same. A sound does not depend on the perception by a sentient hearer. Examining the question, there are three conditions that set the scenario:

1. A tree falls - It is presumed that the tree falls through other trees branches and strikes the ground in a manner that makes satisfying "Thunk!" all of which activities generate sound waves and or vibrations. This is technically a sound or colloquially a noise.
2. in the woods - This is an ecosystem filled with receptors some definitely sentient (humans) and some of debatable levels of sentience (deer, raccoons etc.) all of which have the capacity of hearing
3. and nobody is there to hear it - Fully sentient beings, humans, are excluded but animals are not excluded.

and a question - does it still make a sound.

In physics, the creation of sound waves in a medium constitutes making a sound or noise. In the smaller definition that a sound can only be present if it is heard, the question only postulates the absence of sentient (human) receptors. The existence of hearing animals in a forest environment would be anticipated/ Therefor the sound would have been heard and even under the more limited definition (strictly physics) there would have been a sound.

Sound (noise) is mechanical energy. It is physically real. A source of sound can (will) make the sound whether we are there to hear it or not. Or whether we can hear it or not. That's more of a "physics" answer, but it is a "real" as anything you are likely to encounter.

The definition of sound is the periodic compression and rarefaction of air. Thus whether a person or animal is around to hear the sound (the experience, sometimes referred to as qualia) or not, does not change the fact that the air is still moved in this way, and a sound is produced.

Most basic answer:
No, because the definition of sound is "something that you hear." No one's there to hear the tree fall, so the tree doesn't make a sound. This answer is valid as long as no details are observed technically.
The answer depends upon the particular definition of sound, whether it is the scientific (created vibrations) or the pragmatic (sound is the interpretation of these vibrations). There is no argument that a vibration occurs which will generate sound under any set of normal circumstances. Some opinions and views follow:

One Possible Answer
Everything that vibrates the air creates the potential for sound, regardless of what conscious being is there to perceive it in the first place. If there is nobody is there to perceive it occurring, then it could not exist as sound, only vibration.

Sound is a subjective interaction with matter. All that sound is, is vibrations through a medium, without humans to perceive it, those vibrations that we call sound, when the tree fell, would make vibrations, but "sound" as we know it, couldn't exist, since no conscious being was there to interpret those vibrations.

A Simpler Answer
For example, if a Deaf person was in the woods and a tree fell, would it make a sound? No, because their auditory system would not pick up the vibrations that make sound. They may feel the lower vibrations in their body, but not the sound.


A Personal Point of View Answer
No matter what, whether heard or not, the tree would make a sound. This conclusion would make sense due to the fact if a tree falls in the forest, and someone IS around to hear it, it WOULD make a sound! The "someone" does not have to be there! As an example, picture yourself as a child living with your mum. Your TV is rather loud, and tunes out all other sounds. Your mum is shouting to you from another room. You can't hear her, but she is making a sound! And maybe you're thinking, "Well the TV is tuning out her voice, so that's why!" Not true! Now picture the same thing, except the TV is not on, and you are lounging on the couch, not deep in thought. Your mum yells at you again, asking for a favor from the upstairs bedroom. Though no other noise is being made except for hers, you still can't hear her! In this description, You're not around, or close enough, to hear your mum's voice! Yet she is still making a sound!

The scenarios above would make a sound, because mum, herself, could hear her own voice. So, I do not agree with that answer and support all the perspectives above the last one. To put it simply, vibrating air is only vibrating air. That does not mean that it is making a sound, because a sound requires sensory organs and a nervous system to process the vibrations and then interpret those vibrations as sound.

Here is my analogy: If a person blows a dog whistle, does it make a sound? Not to a human, but only if there is a dog close enough to hear it.Then it would make a sound.

So the answer really should be, in my opinion: if a tree falls in the woods it does not make a sound unless there is anything from an insect to a human being to hear it. It Depends on Factors Involved It depends how hard the tree fell. What if it fell so hard that it can be heard half way around the world? Also are we assuming that the vibration in the air is not sound until it reaches our ear? What is the speed of sound? Is a ball not a ball until we catch it? Is wind not wind until we feel it? Does a chair exist to a blind individual until the individual sits in it? Sound exists whether we are around or not. It is only the matter of if anyone is around to translate the sound into information. Another Opinion I think that it does make a sound because if it makes a sound when we are there then why would it not it if we were not there?

If I knock on wood we all hear the same thing so we cannot change what it sounds like on our own (maybe small differences but barely).

So the sound is not completely in our mind; meaning that it must make a sound no matter if anyone is there or not

Really it Would
The reason it would is the same reason you don't hear much Japanese in America. Some one makes that sound and others hear it, but you don't. The answer is yes because you may not hear it and no one else will, but it will make a noise. It's the same as if you weren't near the forest but another was and a tree falls. They hear but you don't. When they tell you they heard a tree fall you believe them. That's because that person heard it but, you did not. Another Opinion Says No When the tree falls and it finally makes impact with the ground a vibration forms (in the same way ripples form when a rock is thrown into still water). This vibration sets out from all directions of the point of impact, if there is a living being within the range that the vibration can travel it will then be interpreted as a noise. If there is no living being within the distance the vibration can travel it will not be interpreted as a "noise", to be a noise it must first be experienced/perceived. So the new question is 'If a vibration is caused by something in the woods is and no one can hear or feel it is it real'? O.K. the only real answer to any metaphysical questions such as these is that consciousness makes the sound into how it will be perceived. Without consciousness the vibration could not be interpreted as a sound. Your conscious thought (the voice in your head asking this question) was the answer to the question all along. Answer Yes, it does. Sound is mechanical energy. And sound will be created when the tree falls. If no one is there to hear it, that does not negate the fact that the sound was created and radiates out from where the tree fell.

No "opinions" are needed. This is a question that is very straightforward. There is nothing rhetorical about this query, nor is there anything mysterious or metaphysical involved. The question asks about what would happen if a tree fell in the forest, and we have to assume it did to run this "thought experiment" to its conclusion. And that conclusion is that there would, indeed, be sound. It's not rocket science. According to Definition of Sound, No. According to Merriam-Webster, sound is the sensation perceived by the sense of hearing. So that means that vibrating air is just that, mechanical vibrations of air molecules. When those vibrations are perceived by the sense of hearing, then they become a sensation; the sensation of sound. That is why we have an auditory cortex in the neocortex of the brain that interprets those vibrations as a tree falling, a bird singing, or the wind whistling through the leaves.

Here is an example: If you never heard a tree fall as it crashed to the ground and you were standing in the woods blindfolded as one fell, you would hear noise. The noise would be the vibrations in the air of the tree hitting the ground. Most likely you would hear something, but you would not know what it was. But, if you had heard enough similar noises before, your brain would then be able to identify the vibrations as being produced by a tree falling. Then it would be a sound.

So, going by the Merriam-Webster definition, the tree would make air molecules vibrate, but would not make a 'sound' if it fell in the woods and nobody was there to hear it.

• The dictionary definition of hearing is "a special sensation, produced by stimulation of the auditory nerve; the stimulus (waves of sound) acting not directly on the nerve, but through the medium of the endolymph on the delicate epithelium cells, constituting the peripheral terminations of the nerve." The sound we hear is the interpretation of the stimulus we receive, which can only be made by some cognition, i.e.- Information processing which must be linked in some way with a stored memory.

Therefore I reason that though the tree will still cause the wave or disturbance of air as it falls; the fact that noise is merely an interpretation of the wave via a sensory organ processed by a developed intelligence, then it follows that if there is no one to hear it fall and process the disturbance it causes, then it does not make a noise.

• Naturally, events happen regardless of whether someone is there to witness them. Sound is a wave that forms due to an action (the friction of the air with our vocal cords produces our voice, and the collision between the tree and the ground produce the sound of the impact). So, if a tree falls it will sound, even if no one hears it it will still have had a sound. The only place where there is no sound is a vacuum, so if a tree falls in the moon then it would not sound, regardless of you being there to hear it or not.
• Even if there is no human to hear or see the tree fall, there is another creature who will hear it. A falling tree may not make a difference to us humans, but it could be a lost home to a squirrel living inside of the tree, which would hear a massive thud as the mass of wood came tumbling down to the forest floor. And now with the population of people at almost 7 billion, it is unlikely for no one to notice a tree fall. But if the tree fell in space, than no one would hear, because sound requires oxygen to resonate, so that organisms can hear it. So what if a tree falls on a planet with less oxygen, say Venus. The sound of the falling tree (depending on what distance you were listening to it from) would be less softer, and being feet from it would still require hearing aids to hear. But it doesn't matter, because the tree would just evaporate into Venus' harsh atmosphere. The noxious gas clouds would melt the tree, or the heat would burn it instantly, therefore concluding that a tree (theoretically speaking) would neither make a sound, nor exist in open space in the first place, because of the extreme temperatures and climate. Trees would only weigh more on Jupiter compared to earth, and if one was planted on their moon, it would be possible for an astronaut to carry it. And it could not fall, it would would just float around in the space time continuum, until being sucked up into a black hole vortex, eaten alive the tree would shrink to no size and infinite density. And do not forget about the civil rights of trees. Talking about them falling is like deciphering whether a person would make a sound if it fell in the forest with no one else around.
• I looked up sound in the dictionary and part of the definition was something that was heard. If no one was in the forest then it did not make a SOUND. It may have made a sound WAVE yet not a sound!
• Yes. The fact that there is no-one there that can hear it does not affect whether the falling tree makes a sound. Humans are not the only species capable of hearing anyway.
• Yes And No Because there is no one around to hear it and yes because of its greatness so it will make a huge sound but nobody will be able to hear it
• Yes because there are animals living in the forest so they will hear it. the tree will also produce sound because the sound waves will still move. [sound waves do not care if there is no one around to hear them]
• Anything that falls will of course make a noise, even if it is too soft to hear, if a tree falls in a forest it is going to hit the ground and make a noise, or if it bangs against another tree it will rustle those leaves, if you drop your remote on the carpet does it make a noise? Yes, if you drop a pencil on the ground, will it make a noise? Yes! even if no one is around to hear it it will make a noise! those molecules will still carry the noise to where they eventually fade out! So in my opinion, it will make a noise!

It depends on how you define "sound". If sound is something that sends out a vibration through the air that reverberates off of our ear drums, there there is no sound. But if "sound" just means that vibration through the air, regardless to whether there are ears to detect it, then yes, it makes a sound.
no because a sound is only a sound if the air waves vibrate the bones in the ear.

Yes, the falling tree makes sound. Sound is mechanical energy. It's the compression and rarefaction of, in this case, air. The falling tree is converting potential (positional) energy into kinetic energy, and some of the kinetic energy is the mechanical energy of sound. The falling tree makes sound. The sound is there whether anyone is present to hear it or not. Anyone who believes anything differently 1) does not understand the question, 2) does not understand the terminology and the meaning of the words, or 3) is lost in philosophy.

And, if you wish to prove it, set up a recording device and place a timed explosive device around the tree. leave the area well before the explosion. Return after the explosion and if the recording device has not been destroyed (by placing it too close to the tree) you should be able to play back the recording, and if all went as planned, you should hear a loud thud shortly after a sharp explosion. Do NOT try to explain your reasoning behind this experiment to the authorities!
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