When I first heard that track in 1970 upon making, for me as a 13 year old, a huge expenditure, I listened to that track over and over and felt that was the direction that music was heading. Exploratory without bounds, unafraid of mistakes, and here were my music heros just letting it all hang out.
One of the great unrecognized jam sessions of all times, I even got my grandfather to listen to it with me, a staunch conservative anti-rock classical music lover he said that the musicians sounded as though they were trying to compose something original, didn't put it down, even though I knew he hated the Beatles. So there must have been something in that music for him that prevented the typical scorn such a style would have received. Especially during the section where they quiet things down a bit and get very deep into that central theme, there's no doubt true channeling was taking place in the room.
George pushed the envelope more than the others during that period, plus he also had more musical friends outside the band. RIP George, we miss you. I see that Claption still plays Isn't It a Pity in concert.
