intresting...
I'm self taught... I've had 1 lesson... I learned A D E major chords.... forgot them... bought a guitar 8 months later and started again...
I'm not sure... FOr me being self taugh has worked out very well.. I've not learnt any whole songs, yet my technique is head and shoulders above the poeple i started wtih... and i dont practice that much... and i corrected alot of my own mistakes with out noticing when how or why.. I just did.
Having said that, there are some MAJOR drawbacks

your on yer own... no other musicain to exchange ideas with, or to watch, or to just chit chat. True you develop a more unique sound, but the music you listen to plays a bigger part in your "sound" (IMO anyway)

You can get seriously bogged down with thoery, just because you missed one small point, you cannot progress.

NO disciplin what so ever! Which is not a good thing, I spend 20 minutes learning something, and i just get up and do something else... to this day, I've never played guitar for more than an hour in one sitting.. I also have weaker hands, because i've never bothered to repeat progressions, or stick to exercises.

You can hit major problems, and a year and a half later, still will be siting there trying and trying, not knowing where it's possible for you or not... like me.. I STILL cant sing and play at the same time, I can do EITHER but not both... If i had a music teacher he'd tell me where i was going wrong, or how to fix it, or to just give up or whatever.

you'll have huge gaps in your knowledge, cos your learning wasn't systematic, and well thought out.

So yeah you CAN learn without a teacher, but it's a hell of lot easier with a teacher.