@William said:
Pantonal vs. atonal is a useless distinction. Pantonality is obviously a class of atonality since all tones simultaneously negate tonality. Schoenberg is however mainly known as a serialist.
A major third a horrible interval? It depends on the scale - tempered or natural or whatever tuning you wish to use.
I agree with John A about how these things are just too subjective to establish as principles. Also about how context is everything. That is what irritated me with Schoenberg's original statement, because he seemed to be removing context. Though perhaps that was not his intention. I also like some of Schoenberg and can easily see why he just had to do something different - after Gurrelieder.
Pantonality and atonality are different in that with pantonality a tonal centre is all important. The fact that Schoenberg is known as a serialist has nothing to do with this distinction.
Regarding the major 3rd check out the example I gave. Talk to any string quartet player about intonation and you won't get any sleep for days... [:)]
DG