Shelley's essay "On a Future State" follows the same line of reasoning as his essay "On Life." He considers it highly probable that thought is "no more than the relation between certain parts of that infinitely varied mass, of which the rest of the universe is composed, and which ceases to exist as soon as those parts change their positions with regard to each other." His conclusion is that "the desire to be for ever as we are, the reluctance to a violent and unexperienced change," which is common to man and other living beings, is the "secret persuasion which has given birth to the opinions of a future state."
If we turn to Shelley's published letters we shall find abundant expressions of hostility to and contempt for religion. Those letters may deserve the praise of Matthew Arnold or the censure of Mr. Swinburne; but, in either case, they may be taken as honest documents, written to all sorts of private friends, and never intended for publication. Byron's letters were passed about freely, and largely written for effect; Shelley's were written under ordinary conditions, and he unbosomed himself with freedom and sincerity.
From one of his early letters we find that he contemplated a translation of the System of Nature, which is frequently quoted in the notes to Queen Mob. He couples Jehovah and Mammon together as fit for the worship of "those who delight in wickedness and slavery." In a letter to Henry Reveley he pictures God as delighted with his creation of the earth, and seeing it spin round the sun; and imagines him taking out "patents to supply all the suns in space with the same manufacture." When the poet was informed by Oilier that a certain gentleman (it was Archdeacon Hare) hoped he would humble his soul and "receive the spirit into him," Shelley replied: "if you know him personally, pray ask him from me what he means by receiving the spirit into me; and (if really it is any good) how one is to get at it." He goes on to say: "I was immeasurably amused by the quotation from Schlegel about the way in which the popular faith is destroyed—first the Devil, then the Holy Ghost, then God the Father. I had written a Lucianic essay to prove the same thing." In the very year of his death, writing to John Gisborne, he girds at the popular faith in God, and with reference to one of its most abhorrent doctrines he exclaims—"As if, after sixty years' suffering here, we were to be roasted alive for sixty million more in hell, or charitably annihilated by a coup de grâce of the bungler who brought us into existence at first."—A dozen other quotations from Shelley's letters might be given, all to pretty much the same effect, but the foregoing must suffice.
A thorough analysis of Shelley's poetry, showing the essential Atheism which runs through it from beginning to end, would require more space than we have at our command. We shall therefore simply point out, by means of instances, how indignantly or contemptuously he always refers to religion as the great despot and impostor of mankind.
The Revolt of Islam stigmatises "Faith" as "an obscene worm." The sonnet on the Fall of Bonaparte concludes with a reference to "Bloody Faith, the foulest birth of time." Shelley frequently conceives Faith as serpentine and disgusting. In Rosalind and Helen he writes—
Grey Power was seated
Safely on her ancestral throne;
And Faith, the Python, undefeated,
Even to its blood-stained steps dragged on
Her foul and wounded train.
In the great and splendid Ode to Liberty the image undergoes a Miltonic sublimation.
Like one fierce cloud over a waste of waves
Hung tyranny; beneath, sat deified
The sister-pest, congregator of slaves.
Invariably does the poet class religion and oppression together—"Religion veils her eyes: Oppression shrinks aghast."—"Destruction's sceptred slaves, and Folly's mitred brood."—"And laughter fills the Fane, and curses shake the Throne."
Mr. Herbert Spencer writes with learning and eloquence about the Power of the Universe and the Unknowable. Shelley pricked this bubble of speculation in the following passage: