I regard Shelley's early 'atheism' and later Pantheism, as simply the negative and the affirmative side of the same progressive but harmonious life-creed. In his earlier years his disposition was towards a vehement denial of a theology which he never ceased to detest; in his maturer years he made more frequent reference to the great World Spirit in whom he had from the first believed. He grew wiser in the exercise of his religious faith, but the faith was the same throughout; there, was progression, but no essential change.
Percy Bysshe Shelley