Christian Science denounces error in all its forms as suppositional. The Science of Christianity knows no mistakes. These do not occur in the kingdom of God, where divine Principle reigns supreme and where man as God's image partakes of the purity and perfection of being.
Error, however, appears as truth to false material sense. Its masquerade is uncovered to that human consciousness which hungers for righteousness and accepts the fundamental teaching of the allness of God, divine Love. Error disappears when its nothingness becomes fully apparent.
The teaching of the Master, Christ Jesus, is specific on this point of error's nothingness. He said of the devil, or evil (John 8:44), "There is no truth in him." Mary Baker Eddy has this to say in "Retrospection and Introspection" (p. 55): "Let us follow the example of Jesus, the master Metaphysician, and gain sufficient knowledge of error to destroy it with Truth. Evil is not mastered by evil; it can only be overcome with good. This brings out the nothingness of evil and the eternal somethingness, vindicates the divine Principle, and improves the race of Adam."