Many of Locke's contemporaries had argued that it was necessary to morality to show that the soul was immortal: only by evidence of their own continuity into the afterlife could men be given adequate reason for behaving morally. In 1682 Locke had, however, denied the ‘usual’ proof of immortality from immateriality because it was not mere existence but the preservation of a state of sensibility that was important. The Essay was agnostic on the immateriality of the soul and argued that it did not matter if men could attain certainty about the soul's immateriality because ‘All the great ends of Morality and Religion, are well enough secured, without philosophical Proofs of the Soul's Immateriality.’ He continued that this was because ‘it is evident, that he who made us at first begin to subsist here, sensible intelligent Beings … can and will restore us to the like state of Sensibility in another world, and make us capable there to receive the Retribution he has designed to Men, according to their doings in this Life’.

Apart from this declaration of men's ‘evident’ restoration to sensibility in another world by God, however, the Essay crucially gave no indication of how men could gain certainty of the existence of an afterlife, of their own resurrection, or of God's punishments for sin.