To speak of 'original sin' is both to affirm that sin is universal and to suggest an explanation of how this comes to be the case, viz that every human being is contaminated by the sin of Adam. John Wesley's one essay in truly systematic theology was on this subject. He considered the Arianism of Dr John Taylor's Scripture Doctrine of Original Sin. Proposed to Free and Candid Examination (1740) the greatest threat in Britain to the historic faith. His reply, The Doctrine of Original Sin according to Scripture, Reason and Experience (1756-57), draws heavily on Watts, Jennings, Hervey and others in defence of traditional teaching. Wesley believed that any attack on the doctrine, if successful, rendered incarnation and redemption unnecessary. But while, for Wesley himself, all are under Adam's fall, none need carry Adam's guilt. Prevenient grace stimulates our response to the call to repent and believe, and saving grace is the great nullifier of sin's disease.
Subsequent biblical, patristic and scientific scholarship has placed serious question marks beside the doctrine as Wesley and others formulated it. It is, after all, sin itself, not original sin, that necessitates redemption; and original sin is not found in the Greek Fathers, but becomes central only with Augustine, who based it upon six or seven texts whose interpretation is now seriously disputed.