By faith alone, the basic principle of Reformation Protestantism. It declares that humanity is justified only by a confident trust in God through the saving merits of Jesus Christ. This confident trust, called fides fiducialis (trustful faith) is present in those who are predestined to be saved. It is, therefore, a work of predestination and excludes the possibility of good works that, on Catholic premises, are also necessary for salvation. Actually this "fiducial faith" is not so much a means of justification as a sure sign of a person's having been chosen to be saved. Those who have such confidence are thereby known to belong to the elect.