The "If a tree falls in a forest ..." riddle

[emmzee]

I saw the famous "tree falling" riddle mentioned in another thread here, and remembered a post I made on my blog awhile back. I'm not sure how accurate my thoughts are/were re the riddle so I figured I'd post here for comments ... the riddle is succinctly given on an episode of The Simpsons:

Lisa: If a tree falls in the woods and no one’s around, does it make a sound?
Bart: Absolutely! [makes sound of a tree falling]
Lisa: But Bart, how can sound exist if there’s no one there to hear it.
Bart: Wooooooo…

Here's what I wrote on my blog almost exactly 1 year ago today:

I think the “tree falling” koan is rationally solvable. The answer is yes, there is sound … but there is no perception of the sound. The sound itself (a series of pressure waves) is the result of the tree falling; our perception of it is when it enters our ear and we interpret it by the process of hearing. Could there be sound in our ear without the sound waves? No, because THAT is the ’sound’. Here’s an example: If someone slaps me, and I feel pain, the pain itself is not the slap, the pain is only the perception of the slap. The slap would still exist even if I didn’t feel the pain, for example, if I were on pain-inhibiting medication.

Furthermore, the idea that a someone must be present at an event when it occurs for it to truly have happened is ridiculous. We know trees do not (under normal circumstances) fall silently to the ground when they fall; therefore if we find evidence that the tree has fallen, we can conclude that it made a sound. Direct observation is not the only way that we can reasonably know that something is true. For example, we know historical truth by examining the historical evidence. We cannot directly observe, say, Abraham Lincoln being shot, or Columbus “discovering” North America, or even Jesus rising from the dead, but we can still be reasonably certain these historical events occurred by studying the available evidence.

Yea? Nay? Note that I have no formal training in philosophy so this might be totally fallacious

 

[Fed]

This is actually a pretty difficult question. If I remember my epistemology class correctly, it all depends on what you mean by "sound". Is a sound the sound waves, the contact those waves make with your eardrum, the nerve impulse that results in a given perception by your brain, or all of these? Usually, we only refer to sounds we can perceive. So if we pretend that there are things that make sound waves but they are imperceptible to us, we wouldn't call those things sounds. Of course, that's just the common meaning.

Really what you're getting to here is the philosophical debate between sensation and reality - does something have an existence beyond the sense data that we perceive? If you were Berkeley, you'd say "no" and therefore the tree falling unperceived doesn't make a sound (or exist, for that matter), since a tree is just a collection of sense data. Without sense data, there is no tree. You can check out the wikipedia entry.

 

[SpazNStuff]

If a mime falls in a forest, does it make a sound?

 

[theQuestionist]

This question is also relevant to quantum physics, and moreover, wave function collapse.

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

Ie, some interpretations would say that until there is an observer to see the tree falling/having fallen, that the tree exists in all possible states.

 

[metherion]

But does the observer have to be human?

After all, forest must have at least more trees around, and usually a plethora of animals with hearing.

Metherion

 

[emmzee]

This is actually a pretty difficult question. If I remember my epistemology class correctly, it all depends on what you mean by "sound". Is a sound the sound waves, the contact those waves make with your eardrum, the nerve impulse that results in a given perception by your brain, or all of these?

Hmmm, the replies so far in this thread seem to suggest that this riddle cannot be answered.

The question is what does "sound" mean here. IMHO, the waves are the sound. If the sound were defined as the vibrations of the ear, then that would mean that the sound exists even if a person who is deaf was standing near the tree. But he/she could not hear the tree falling even if their eardrum vibrated.

The sound is also not, IMHO, the nerve impulses in our brain. This is the interpretation of the sound; our brain analyzes the outside stimulus and perceives it. Perceives what? That which is being perceived is the sound. If we eat a hamburger, and taste it, the sensation/perception of tasting it is not itself the hamburger.

Really what you're getting to here is the philosophical debate between sensation and reality - does something have an existence beyond the sense data that we perceive? If you were Berkeley, you'd say "no" and therefore the tree falling unperceived doesn't make a sound (or exist, for that matter), since a tree is just a collection of sense data. Without sense data, there is no tree.

I understand the theory, but do any of us really believe that this is true? That, for example, if no one physically perceived a volcano erupting, that we would not still conclude that it had based on other evidence? It would seem ingenuous to say "Well, the village is destroyed, and we can see the path that the lava flowed, but since no one was actually around to see the volcano erupt, we can't say that it did."

There's a couple possible options in response to this riddle (aka "koan"), which do you guys go with:
1) Yes, it makes a sound.
2) No, it doesn't make a sound.
3) It may or it may not, but we can't really know.
4) The question is ambiguous so it can't be answered.
5) Yes, it makes a sound, but only if the tree falls on a gopher

I'm still going with 1, though I think there's some merit to 4. In the Simpsons conversation above, there may be some equivocation of the word "sound" going on there.

 

[GratiaCorpusChristi]

If a mime falls in a forest, does it make a sound?

Only if it falls off the cliff, in which case the sound you hear will be me laughing.

Oh, and the answer is yes if you're an Aristotelian or Lockean, no if you're a Kantian or continental rationalist or Scotist empricist, and 'what a dumb question' if you're Wittgenstein.

(boy I hope someone gets that...)

 

[dayhiker]

I'd go with 1 also.
If the world wasn't that way, then if noone had been there to see the tree grow it wouldn't be there to to fall and make a noice!

As for the trees existing in all possible - I konw I'm not conciously choosing which state I see or hear the trees in!

I'm sure that anwsers nothing in that world of thinking.

dayhiker

 

[Fed]

The sound is also not, IMHO, the nerve impulses in our brain. This is the interpretation of the sound; our brain analyzes the outside stimulus and perceives it. Perceives what? That which is being perceived is the sound. If we eat a hamburger, and taste it, the sensation/perception of tasting it is not itself the hamburger.

See that's where it gets tricky. Apart from touching, smelling, seeing, and tasting the hamburger, what is a hamburger? Think of it this way - a table is hard, makes a certain sound when you knock on it, etc. But is it really more than that? I think so, but if you try to give a reason, you find that describing things beyond their immediately perceivable qualities does seem tenuous. What is a table beyond what I perceive?

I understand the theory, but do any of us really believe that this is true? That, for example, if no one physically perceived a volcano erupting, that we would not still conclude that it had based on other evidence? It would seem ingenuous to say "Well, the village is destroyed, and we can see the path that the lava flowed, but since no one was actually around to see the volcano erupt, we can't say that it did."

No one's saying you discount evidence. We can see evidence of certain events and conclude they happened. The question is, does something exist if it's never been perceived (directly or through evidence)?


Really, the main point of the question is to realize that even though we believe things have an existence apart from their sense data, our reasons for believing it aren't very philosophically rigorous. It's just something that "seems" right.

 

[R3quiem]

If sound is defined as the vibrations transmitted through a medium, then there is no reason to believe those vibrations don't occur just because someone isn't around to hear them. Just because we aren't there to detect the sound with our ears doesn't mean they aren't there.

If everyone on Earth closes their eyes, does the sun stop producing light? We don't have power like that over the sun, nor a tree.

 

[R3quiem]

Really, the main point of the question is to realize that even though we believe things have an existence apart from their sense data, our reasons for believing it aren't very philosophically rigorous. It's just something that "seems" right.

That's a fair point. But since we only have certain tools to go by, we have no choice but to trust them. I think that's why the movie "The Matrix" was so popular (apart from it being just downright cool.)

 

[GratiaCorpusChristi]

That's a fair point. But since we only have certain tools to go by, we have no choice but to trust them. I think that's why the movie "The Matrix" was so popular (apart from it being just downright cool.)

That and because Americans are Gnostics.

 

[lawtonfogle]

This question is also relevant to quantum physics, and moreover, wave function collapse.

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

Ie, some interpretations would say that until there is an observer to see the tree falling/having fallen, that the tree exists in all possible states.

That would beg the question, does the tree count as it's own observer? Also, one would have to define what is observing.

 

[theQuestionist]

That would beg the question, does the tree count as it's own observer? Also, one would have to define what is observing.

Hehe yes this is quite a confusing topic. Some quantum physicists propose that an inanimate object can act as an observer...ie, the Universe is constantly observing itself.

I forget the name for that exact theory....but as far as I remember it's listed on the wikipedia entry for the Schrodinger's Cat dilemma, as one of the possible problems with it.

 

[Yekcidmij]

This question is also relevant to quantum physics, and moreover, wave function collapse.

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

Ie, some interpretations would say that until there is an observer to see the tree falling/having fallen, that the tree exists in all possible states.

Impossible. A tree cannot be in a state of alive and dead at the same time.

If left unobserved, my house cannot exist as charred remains and a full complete house at the same time.

 

[Fed]

Impossible. A tree cannot be in a state of alive and dead at the same time.

If left unobserved, my house cannot exist as charred remains and a full complete house at the same time.

A single photon can pass through two slits at once.

 

[Yekcidmij]

A single photon can pass through two slits at once.

So does that mean a tree exists in a state of standing and a state of fallen at the same time. No. This is against logic.

 

[Fed]

So does that mean a tree exists in a state of standing and a state of fallen at the same time. No. This is against logic.

Well quantum physics applies to the subatomic world. We can't see quantum effects macroscopically, as far as I know. It was more a point of questioning your intuition and what seems obvious.

 

[emmzee]

Well quantum physics applies to the subatomic world. We can't see quantum effects macroscopically, as far as I know. It was more a point of questioning your intuition and what seems obvious.

Point taken, we should question our intuitions, though the photon example has no direct relevance to the tree.

I'm not sure this is a case of "intuition", though. AFAIK, intuition usually refers to 'knowing a fact without knowing how we know it' ... like certain laws of logic, ex. the law of non-contradiction. (Though I may be incorrectly equating "intuition" with "properly basic belief" ... or are these basically the same thing?) In the tree example, we're making a choice (if we say yes, it makes a noise) based on our knowledge of how the physical world operates, not intuition. Given our previous knowledge of what happens when trees fall (they make sounds) it's reasonable to say that (barring any extraneous circumstances) a particular tree that we find fallen made a sound when it fell.

This of course brings us back to what is meant by "sound" ... although as I think about it, the phrasing of the riddle itself seems to rule out certain interpretations of the word. "How can it make a sound if there's no one around to hear it?" The hearing is clearly differentiated from the sound there (the tree "makes" a sound, it's not our ears or brain that "makes" it), so the sound seems to exist independently from the hearing, yes?

I've spent way too much time writing about this heh.

 

[ericd777]

Hello emmzee,

It still amazes me how people can go around and around, sometimes for years, when all that is needed is definitions of the terms people are using to end their confusion. Political "liberal" and "conservative" arguments, for example, are inconclusive when no one defines these terms beforehand.

It is the same here. All that is needed is a definition of the word "sound". Simply put, if sound is defined as vibration of matter the tree makes a sound, but if sound is defined as vibration of a human eardrum then the tree does not make a sound. The first order of business in a logical discussion is to define the terms used.

There is a lot of "ever learning, and never able to come to the knowledge of the truth" going on everywhere. I think most people have the goal of never being able to come to the knowledge of the truth. (Present company excluded of course.)