Great answer Krystal. And, good question to ask Pebbles.
Singleness of Purpose IS what makes AA -- AA, and not some other A.
Rather than get into a lengthy discussion, which we've already covered here a few times in this forum -- I'd suggest reading the Chapter on Tradition Three, in the book 12 Steps & 12 Traditions. Also, to read the Long Form of the Traditions in the Big Book, and that pretty well says it all.
This is a common question. It seems to be most often asked by those that have been to NA, seeking help for a drug problem -- and they want to go to AA meetings... primarily because NA is weak in recovery in their area.
I often answer the question by asking three questions:
1. IF NA was stronger in your area -- is this where you would go? (Often, the answer is yes).
2. Do you think it's a good idea -- that people from NA, should come to AA -- and do what they are doing in their local NA -- and make AA just as ineffective and as weak as their NA?
3. Why don't you just go to NA, if that's what would be better for you -- and support them, to make it stronger?
When I first landed in AA in December of 1985, shortly after learning that they had NA near by -- I figured "well, heck! I should probably be there, too... because of all the drugs that took while drinking!"
NA was a very strong group... and, the group I decided to attend was one of the founding NA groups in Southern California. And, it was packed w/ NA Oldtimers.
When it came time for me to introduce myself, I picked the newly popular term that developed in the early 80's... as "My name is Dallas, I'm an alcoholic-addict."
Nearly the entire room full of NA Oldtimers slamed me with "Did you shoot heroin? Did you fix dope?" I said... "No, but I sure did take a lot of it!" The very promptly "ran me out of the meeting"... explaining "you don't belong here -- you should probably go back to AA." They went on to explain that NA was for "Narcotic's Addicts"... They founded their entire program for "heroin addicts" -- it wasn't for "just any kind of drug addict."
NA used the same 12 Traditions as AA -- except they modified it for their Primary Purpose -- and were very strongly committed to their 3rd Tradition and their Singleness of Purpose in helping Narcotics (heroin) Addicts. This is also why "Cocaine Anonymous" was started in 1986/87. And, later on, anonymous groups such as "Crystal Meth Anonymous."
My personal observation has been that the 12 Step Anonymous Organizations -- that "stuck to" their 3rd Tradition, not only survived, but they grew, and those that sought their help and their Fellowship -- recovered. And, the Anonymous Organizations that didn't stick to their Singleness of Purpose -- rapidly began to get worse, rather than better. And... what do they often do??? Head over to AA, proclaiming "acceptance is the answer".......
btw: Acceptance is NOT AA's Answer. AA's Answer is: The 12 Steps & the 12 Traditions.