Does this mean that nothing that glitters is gold, or does it mean that not everything that glitters is gold? The wording sounds as if the former, to me, but the context seems to suggest the latter.
Erm … what context? 
Just the obviousness that some things that glitters are gold.
Glitter glitters and it can be red, blue, purple, silver, etc.
You make a valid point.
Does gold, in fact, glitter?
Yeah. Especially if you shellac it.
Send me all your gold; I shellac iit just fine. 
More context than anyone really wants… At first, I thought that maybe both meanings can be found among the quotes. On reading them again I think Walden’s right, and they all mean his second choice. I guess the first interpretation does sort of defy logic, except on an entirely metaphoric level, in which case… Oh, dear, now I want to change my mind again.
You wax eloquent, as usual, scottie. If I hadn’t written, it would have been a fine finish!
Carol
Very punny.
Albedo judge of that. 
Ah the master at work!
When we apply a proper boolean syntactical analysis to the original we see it contains the exception to the exclusion - the modern translation incinerated the meaning intended by the bard.
Curiously, the meaning has survived by implied context.
Strange to see that language is supported by assumption - and what we assume is usually what undoes us.
When I hear my budgie say “Polly wanna cracker” - i naturally assume he’s talking about the toy explosives we used to play with as kids before they were (sadly) banned. As a result, letterboxes are in better shape these days and Polly wants more feathers. 
All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost.
From the ashes a fire shall be woken,
A light from the shadows shall spring;
Renewed shall be blade that was broken,
The crownless again shall be King.
–J.R.R. Tolkien
–James.tar.gz
That reminds me of Jesus.
Wouldn’t be the only time Tolkien used Christian symbolic language.
Yes, when I first read that, I did ponder the total boolean exclusion - meaning that gold never glitters. = to absolute set “gold” apply absolute negation of property “glitter”. Since the poem was set in the absolute context “of Aragorn” I took the line to communicate that Aragorn was keeping a low profile i.e. not glittering and being in a reduced context did not apply to anything else that might be gold and not electing to be covered in crud. . That’s assuming Tolkien was the pre-eminent language stallwart he is painted to be.
So I’ve heard. I’ve never read Tolkien.
Perhaps I might I should, if only I had the time.
Your commendably relentless application of Boole to Shakespeare and now Tolkien reminds me of E.B. White’s remark about humor: …[in these cases, the poetry] “can be dissected, as a frog can, but the thing dies in the process and the innards are discouraging to any but the pure scientific mind.” 
The amazing thing about people is that they nearly always make time to do what they want to do.
If you used 15 minutes of the time you waste here, you could get a lot of things done.