@William said:
If this is true it shows the obvious equation: DISSONANCE = HORROR
For most people this is true. Students very often use words like "creepy" when asked to comment on music with unresolved dissonances.
I think for the average listener (who, lets face it, is usually rather uneducated musically) a large part of this reaction is due to music's use in film. Your average Joe listener needs to see an image when he hears music.
Schoenberg's comments re beauty I take with a pinch of salt. There is almost no point talking about an interval as an aesthetic entity. How does the thing get used in context? There are achingly beautiful minor seconds in tonal music, and achingly dull ones in non-tonal music...
I always supposed that Schoenberg was on his didactic rant about emancipation of the dissonance, trying to force everyone to think like him.
best,
John