What's Soul music?

Annoyingly enough the Motown video below was working last week but now it's just sat there teasing. I'll find it again but in the meantime - what is soul music? I'd say Bjork is part of soul music. Vespertine is one of my top 5 albums of all time - listen to it outside in the dark in summer or at Christmas with just fairy lights (yes I'm a hippy). First time I heard that album I said 'if there is a heaven they're playing this'. Part of my Bjork-love is that she's such a complete artist. This video is part of the reason I say that - Chris Cunningham is such an amazing director with an incredible range (sic: Window Licker & Come to Viddy by Aphex Twin) and this video alongside the song both breaks my heart and expresses things for me I could never articulate...

By the way I will keep on posting things on here to amuse myself indefinitely...