Such is the defiance involved in the famous saying that an impartial critic, Johann Adam Möhler, in his “Symbolism” says: “Although too much stress must not be laid on the passage, seeing how overwrought and excited the author was, yet it is characteristic enough and important from the point of view of the history of dogma.”[589] G. Barge, in his Life of Carlstadt, says, that Luther in his letter to Melanchthon had reduced “his doctrine of Justification by faith alone to the baldest possible formula.”[590] “If Catholic research continues to make this [the ‘_Pecca fortiter_’] its point of attack, we must honestly admit that there is reason in its choice.” The last words are from Walter Köhler, now at the University of Zürich, a Protestant theologian and historian, who has severely criticised all Luther’s opinions on sin and grace.[591] One of the weak points of Luther’s theology lies, according to Köhler,[592] in the “clumsiness of his doctrine of sin and salvation.” “How, in view of the total corruption of man” (through original sin, absence of free will and loss of all power), can redemption be possible at all unless by some mechanical and supernatural means? Luther says: “By faith alone.” But his “faith is something miraculous, in which psychology has no part whatever; the corruption is mechanical and so is the act of grace which removes it.” In Luther’s doctrine of sin, as Köhler remarks, the will, the instrument by which the process of redemption should be effected, becomes a steed “ridden either by God or by the devil. If the Almighty is the horseman, He throws Satan out of the saddle, and _vice versa_; the steed, however, remains entirely helpless and unable to rid himself of his rider. In such a system Christ, the Redeemer, must appear as a sort of ‘_deus ex machina_,’ who at one blow sets everything right.” It would not be so bad, were at least “the Almighty to overthrow Satan. But He remains ever seated in heaven, i.e. Luther never forgets to impress on man again and again that he cannot get out of sin: ‘The Saints remain always sinners at heart.’”