John asked:

Who originally asked the question, "If a tree falls in the woods and there is no-one there to hear it
does it make a sound?"?

============

I would like to know the answer to this one too. I'm afraid that the best that I can offer is a partial
debunking of the most popular answers.

1) I have seen it claimed that the question is a Zen koan. This is true in a way: it could be read as a
koan — a paradoxical question, intended as thought-provoking rather than straightforwardly
answerable. However, it is not to be found in any of the principal collections of canonical koans (the
Blue Cliff Recordsor Pi-yen-lu; the Gateless Gateor Wu-Men Kuan; the Book of Serenityor
Ts'ung-jung lu) and I've never seen a specific attribution to any such source.

For more information on koans see:

http://www.ciolek.com/WWWVLPages/ZenPages/KoanStudy.html

2) Scientists and engineers sometimes argue that the question is a straightforward one, intended to
illustrate the distinction between 'noise', radiant mechanical energy in air, and 'sound', our perception
of such energy, that is, heard noise. Hence the tree makes a noise, but cannot make a sound, a
heard noise, because there is no one to hear it. This answer tends to irritate people whose
dictionaries are less prescriptive. A more sophisticated way of expressing the same point would be to
say that the appearance of paradox is merely a result of equivocation between the two senses of
'sound'.

It is possible, but seems unlikely, that the question may have originated as an illustration of this
contrast in a physics or engineering textbook.

3) The question is sometimes attributed to George Berkeley, and routinely comes up in philosophy
tutorial discussions of his work. This is understandable: Berkeley's metaphysics has the apparent
consequence that unperceived objects do not exist. Only apparent, since God plays a central role in
Berkeley's system as the guarantor of the continued existence of all objects. Although unperceived
trees are amongst Berkeley's favourite examples, he does not consider their falling or making sounds.

For examples of what Berkeley didsay about trees, see his Principles of Human Knowledge, Part I,
23, or this passage from the first of the Dialogues between Hylas and Philonous:

"Phil.: How then came you to say, you conceived a house or tree existing independent and out of all
minds whatsoever?

Hylas: That was I own an oversight; but stay, let me consider what led me into it. — It is a pleasant
mistake enough. As I was thinking of a tree in a solitary place, where no one was present to see it,
methought that was to conceive a tree as existing unperceived or unthought of; not considering that I
myself conceived it all the while. But now I plainly see that all I can do is to frame ideas in my own
mind. I may indeed conceive in my own thoughts the idea of a tree, or a house, or a mountain, but
that is all. And this is far from proving that I can conceive them."

or, from the third dialogue:

"Phil.: ... Ask the gardner, why he thinks yonder cherry tree exists in the garden, and he shall tell you,
because he sees and feels it; in a word, because he perceives it by his senses. Ask him, why he
thinks an orange tree not to be there, and he shall tell you, because he does not perceive it."

The association between Berkeley and trees has been reinforced by Mgr. Ronald Knox's celebrated
limerick:

"There once was a man who said, "God,

Must think it exceedingly odd

If he finds that this tree

Continues to be

When there's no one about in the Quad.""

and its reply (attributed to Bertrand Russell).

"Dear Sir, Your astonishment's odd:

I am always about in the Quad.

And that's why the tree

Will continue to be,

Since observed by, Yours faithfully, God."

For an explanation of how these limericks misrepresent Berkeley's position, see:

http://easyweb.easynet.co.uk/~ursa/philos/berkeley.htm#quad

Andrew Aberdein