richard-kubina funny, i was gonna say, my guess would be that early humans used sounds we would call musical to signal to each other, when hunting or in battle, then eventually, in everyday life. like now: we use a quick, short whistle to get attention. or the infamous "wolf whistle". point is, i think music was first used as a signaling method early on which sort of hardwired our brains, maybe even our genetic code, such that certain sounds make us feel certain ways.
that's my theory at least. the signaling aspect, i think that's solid, but the connection to emotions we have now, hearing music, is just pure speculation.