 Music journalist Carol Clerk describes "Revolver" as having been "decisively informed by acid", following John Lennon and George Harrison's continued experimentation with the drug LSD since the spring of 1965.Through these experiences, the two musicians developed a fascination for Eastern philosophical concepts, particularly regarding the illusory nature of human existence.Despite his bandmates' urging, after Ringo Starr had also partaken of the drug, Paul McCartney refused to try LSD.