To sum up:

The Rosetta Stone = a stone tablet that allowed Eqyptoglogists to intepret hieroglyphics because the stone contained Hieroglyphics, Ancient Greek, and a third language. So in one sense, The Rosetta Stone is itself a key.

However, the Rosetta Stone contained a key within a key. The way scholars broke the code of the Rosetta Stone was through the matching up of cartouches (pardon spelling) - oval 'monograms' for the names of the pharoahs and major egyptian people.

Now - to tie it to Tool - much of Tools music revolves around the opening of the Third Eye - an act which by the nature of the description necessitates a key. In the case of Tool's music, the key is an act of will- an examination of self that allows an introspection to break down the barriers that divide the conscious from the expanse of the unconscious.

Hence the conversation with a 'psychotherapist' in Lost Keys.

In Rosetta Stoned, if you think about the play on words in the titled, to be Rosetta Stoned is twofold in meaning:

1) To be placed in a situation that requires a Rosetta Stone

2) To be the Rosetta Stone yourself.

Tool's trend of introspection and "prying open my third eye" suggests the second intepretation, but the Rosetta Stone, as I mention above, sort of needs another Rosetta Stone (the cartouches). I think that the references to Aliens, religion, philosophy, drugs etc refer to the different languages on the stone, and suggest that in order to unlock them one must find the key that connects them - possibly the self.

However, as I mention in another post - one could call a parallel reference from the movie "Pi" - looking for a pattern in the stock market that is also the name for God that is also a master code, etc. The main character of pi physically tortures and abuses himself mentally in order to obtain this code only to realize that the code was not worth the path - resulting in him lobotomizing himself.

In this case we see a character who has not reached the solution, who also has not broken, but has reached such as state that he has "shit the bed."

Curiously, while pi leaves the viewers with the feeling that the overall message might be that there are some things we are not meant to know, Rosetta Stoned seems to suggest that the pursuit is still undergoing.

However, I do not understand all the lyrics and haven't had as much of a chance to think about this song as I have some of the others, so if anyone has any comments or better ideas or corrections, let me know.