Sound waves emanate from falling trees

The notion that when a tree falls down in an uninhabited forest it does so in silence is one of the “old chestnuts” of philosophy. Is there still debate about it? My opinion on it is thus:

In the phenomenal world, there’s the subject side and the object (or representation) side. When a tree collapses, sound waves are transmitted outwards from it - the objective side. If a man (or any animal) is nearby, he experiences the “sound” of it - the subjective side. So, if no-one is there, only the objective happens, hence the idea that the fall is silent. “Silent” thus means “without the sensory experience of sound”, not “without sound waves”.

Anyone who asserts that in a forest where a tree has fallen down there were neither subjective nor objective sounds is, IMO, guilty of the same empty thinking that leads to solipsism. (Before such a man addresses this issue, he should explain why he isn’t a solipsist.)

The obvious feint would be to ask you how do you know it produces sound waves when falling.

I know it does - in the same way as I know that a pendulum will oscillate with a constant time period if I release it. Absolute certainty (like in maths)? No, but I have faith in the predictability of non-extreme macroscopic phenomena. What better thing to have faith in?

I’m sure the faling tree emanates the waves… I just don’t know why anyone would be presumptuous enough to call them sound waves?

esse est percipi


Sound, by definition, is the subjective experience of waves of particles vibrating the eardrum, which is then interpreted by the brain.

If a tree fell in a forest, but not a thing on this planet had the ability to hear, it would not make a “sound.” It would produce the waves of particles crashing into each other, but sound requires a receiver.

It takes two to tango.

Spot on, d0rky.

Imp: if you weren’t present in the forest, but another man was, and he told you afterwards that the fall had been noisy, would you believe him?

not necessarily


I’ll elaborate on this man: he’s always honest, and you and he have witnessed many events before, and have always agreed on what happened. In other words, he isn’t bullshitting or talking about something else.

My thinking is this: if we’re present at a felling, we know with certainty that it’s noisy, because we’re physically hearing it. If we aren’t there, then we hear nothing, so can’t have such certain knowledge about it. If, however, an observer is there on our behalf, and reports back to us later, then we’re “detecting” the sound in a less direct manner. The same is true if we listen to a tape recording of it.

and if an observer is there and claims that the dead are walking, you believe him?


You are comparing somebody who is claiming to hear something, which happens often on a regular basis to people every day, to somebody who is claiming to have witnessed something that has never before been proven…

This is quite a difference, and I find this comparison to be a very poor one.

What d0rky said.

This is like saying that a man who actually hears a falling tree might’ve been “hearing things”.

noisy is too vague


Absolutely true.

There is no such thing as “sound waves” in and of themselves.

“Sound” waves are simply what we call the air displacement with relation to someone “hearing” that air displacement.

Sound is a human experience, nothing more – sound does not exist without a hearer, as sound is an effect, not a cause, an effect that occurs only within a person “hearing” the cause of it.

So, if the tree falls in a forest and there is no one there to hear it, it still causes air wave displacement, but without a “hearer” to “hear” that air displacement, no “sound” occurs.

Is this a step-down from your original position? :wink:

Let’s call it a creaky thud then.

not at all. I said it depends if you believe the witness.

but even that is beside the point.

the fact that there is a witness makes my original point completely.



Part of why I am not a solipsist.

The Incoherence of Solipsism

With the belief in the essential privacy of experience eliminated as false, the last presupposition underlying solipsism is removed and solipsism is shown as foundationless, in theory and in fact. One might even say, solipsism is necessarily foundationless, for to make an appeal to logical rules or empirical evidence the solipsist would implicitly have to affirm the very thing that he purportedly refuses to believe: the reality of intersubjectively valid criteria and a public, extra-mental world. There is a temptation to say that solipsism is a false philosophical theory, but this is not quite strong or accurate enough. As a theory, it is incoherent. What makes it incoherent, above all else, is that the solipsist requires a language (that is a sign-system) to think or to affirm his solipsistic thoughts at all. Given this, it is scarcely surprising that those philosophers who accept the Cartesian premises that make solipsism apparently plausible, if not inescapable, have also invariably assumed that language-usage is itself essentially private. The cluster of arguments - generally referred to as “the private language argument” - that we find in the Investigations against this assumption effectively administers the coup de grâce to both Cartesian dualism and solipsism. (I. § 202; 242-315). Language is an irreducibly public form of life that is encountered in specifically social contexts. Each natural language-system contains an indefinitely large number of “language-games,” governed by rules that, though conventional, are not arbitrary personal fiats. The meaning of a word is its (publicly accessible) use in a language. To question, argue, or doubt is to utilize language in a particular way. It is to play a particular kind of public language-game. The proposition “I am the only mind that exists” makes sense only to the extent that it is expressed in a public language, and the existence of such language itself implies the existence of a social context. Such a context exists for the hypothetical last survivor of a nuclear holocaust, but not for the solipsist. A non-linguistic solipsism is unthinkable and a thinkable solipsism is necessarily linguistic. Solipsism therefore presupposes the very thing that it seeks to deny. That solipsistic thoughts are thinkable in the first instance implies the existence of the public, shared, intersubjective world that they purport to call into question.

TY for the info, bdhanes.

Here’s an alternative statement of what I’m trying to say. If a subject is within range of a phenomenon, then he senses it. If he’s outside its range, then he doesn’t sense it, and some people would say that that phenomenon - deduced afterwards to have happened by scientists - didn’t happen at all, or rather, can’t be known about.

That last argument is that if something doesn’t occur in the subject’s representation of the world, then he can’t believe it happened (cf. the falling tree issue). But if a second subject witnessed the phenomenon, and reports back to the first, then the latter can believe that it took place. This demonstrates that you don’t have to have direct experience of a given day-to-day phenomenon to know that it occurred.

This second subject could be replaced by scientific reasoning (eg, you see a fallen tree and deduce that it had to have fallen down).

There’s a second point to be made. In the above, a subject was present at the felling, suggesting (to some) that you need one in order for the event to occur. I don’t think you do, with my reason being that any given event in the world has three forms: the in-itself, the objective, and the subjective. Imagine a man thinking: his brain activity is the objective, his thoughts (known only to him in his consciousness) are the subjective (the correlative of the objective), and the pair of these have an in-itself, roughly as set out by Kant. When animals represent the world as they do, they create the objective equivalent of the thing-in-itself. The thing in itself thus has an objective form, whose existence is subject independent. It’s this independence of subjects that allows us to say that things that happen outside anyone’s range can in fact be considered to have happen in the physical.

I hope this is understandable.

your interpretation of kant is incorrect…

and it isn’t knowledge, it is supposition and guesswork…

the dark side of the moon is made of green cheeze…