Tree falls in the woods:

I usually answer by saying, “Wether it is heard or not, there is a displacement of air.”

Welcome to the Straight Dope, Cabyland! It’s customary to give a link to the article in question like If a tree falls in the woods… That way, we don’t have to guess what you’re talking about.

In this case, knowing the context has a HUGE impact on the way your response can be taken.

One can also answer that until it is observed the tree remains in a quantum superposition of fallen and not-fallen states, and thus the answer is indeterminate.

If one wants to be obnoxious, I mean.

What, it’s Schrodinger’s Tree now? If it falls, it makes noise, as every tree to fall since the dawn of time has done. Whether or not someone is there to hear it is irrelevant. Timberrrrrrrrrr!

‘One of the recurring philosophical questions is:
“Does a falling tree in the forest make a sound when there is no one to hear?” Which says something about the nature of philosophers, because there is always someone in a forest. It may only be a badger, wondering what that cracking noise was, or a squirrel a bit puzzled by all the scenery going upwards, but someone.’ - Terry Pratchett.

Pratchett is half-right. What constitutes an observer anyways?

But you can postulate scenarios where there are no observers without brains with which to observe. Say a dead tree in the middle of the great Erg, with no life within a hundred miles.

According to strict Quantum Physics, no the tree cannot even be said to have fallen, without someone to have observed it.

With brains, that is.

[Work on editing skills! :smack: ]

It interacts with the environment directly, meaning it is observed.

The answer, semantically, would seem to me to be an unqualified yes. It makes a sound, although that sound may not become sound until heard.

Now, if the question was “If a tree falls in the forest and there is nothing to hear, is there a sound,” then it would be ambivalent. One’s made, because nothing distinguishes the two situations from the “maker” perspective between heard and not-heard. They are therefore identical.

Of course there’s a sound.

When a tree falls in the woods, every treehugger screams in sympathy.


My political party (green) certainly does…every single time they cut one down and don’t replace it :rolleyes:

What if a tree falls in a forest and the only observers are a passing group of philosophers?

It seems to me that this discussion is largely academic. The dictionary defines “sound” as both transmitted vibrations, and the sensation of hearing. To say that the sound of the falling tree can only be defined by one of these definitions is tantamount to saying the Sun doesn’t shine, because it isn’t “a person distinguished in an activity or a field”.

The tree clearly makes a sound by one definition, and by two definitions if it is heard.

It does boil down to semantics, most things do.

The answer I’d been satisfied with, until now, was that the unobserved tree makes a sound, but not a noise.

But what if an unobserved tree falls in a vacuum?

Onto a treadmill.

Ducks and Runs. Far, Far Away.

And then plummets down to the bottom of the Marianas Trench…for 20 minutes or so.


I think the framers of the original question knew that, but it’s migrated cultures and now people are demanding an answer to question that’s not meant to have one.

It makes the same sound as one hand clapping.
Don’t get it? Then you haven’t mastered zen.

Or your domain.

We can only hope the tree falls on them.

And a more important question - If a man is standing in the middle of a forest and he opens his mouth to speak and there is no woman there to hear him, is he still wrong?