i think of jazz as the beginning of psychedelic music.
if u trace the roots back of jazz it goes back to musicians who started using marijuana in early 1900s. They played a wacky style that was intellectual, outside the box, relaxing, and just fun. the whole conecpt of jazz is psychedelic. take allan holdsworth - every note he plays is so outside the box yet fits together and flows so nicely and subtley melodic. jazz takes unexpected twists and turns more than any other you music will find. the entire genre title of "progressive" to is linked to jazz in my eyes. take rock or metal and "jazz it up a bit" - extend those chords, add some complexity to the song structure, create sounds outside the box, etc - and its progressive.