"First there is a mountain. Then there is no mountain. Then there is." Not just a Donovan lyric, it is also part of Buddhist and Taoist literature going back more than 2500 years. (I assumed, after reading the Tao Te Ching, that the concept for the lyric had been lifted from there, but later found out it came from Qingyuan Weixin through D.T. Suzuki.)