I have a Pee Wee Les Paul. I have a nut extender. Now I have a guitar in open G. That is, open G as if it was open D and capo'd up five. GDGBDG. It's a Pee Wee, built for the little ones, and the little ones have never taken to it. So, it is my lap steel #2.
This makes me think about tuning.
The standard guitar tuning is a bit of a mess. Scales lay out beautifully when you tune in fifths, as any mandolin player will tell you. It's hard to see the parallels and overlaps when you tune in fourths, like guitarists do. And then there's the bump, the major third between the second and third strings. Or fourth and fifth strings. It works. It makes chording fairly easy. Easier, I say, than in fifths like a mandolin, and as easy, in a different way, as everything put out in front of you with a keyboard.
But where did it come from?
Richard Lloyd describes the tuning as coming from a pre-decided use of an E as the low string and fourths and trying to find something more useful than the C and F resulting.
It is a reasonable take, and as a "here's why, now go away" explanation, it works as well as any other and better than most. But it doesn't compel me. It sounds like a maker came up with a problematic design (EADGCF) and eventually a compromise (EADGBE) came about. It starts with E, but the E bass string is probably the last string added to the modern guitar*, and thus it makes it unlikely that the tuning started with the deification of the E.
* The low B string, actually, is the last string added to the modern guitar, and it's still not universally accepted. But it is used for the same reason the E was at first, to give a deeper ringing bass note there.
Bob Brozman argues for the centrality of the G tuning (DGDGBD), saying that's the first open tuning every guitar goes for. Not just "Open G", but that tuning specifically. That tuning shares a G chord - D G B - with standard. Other stringed instruments, like the ukelele and the banjo, share a standard open G, although one might wonder if there is a standard banjo tuning, and the other members of many bluegrass bands wonder aloud if you can tune a banjo and how could you tell if it was tuned.
So, is the G-B third a compromise, or is it built in? What's your take? And, incidently, if I say the sixth string, which string would you count that as, the high E or the low E?