This evidence is seen in the invincible stability of the Church and its unity of faith, the incontestable miracles never ceasing within it, the grand figures of its Saints and Martyrs, virtue in the various classes, a virtue increasing in proportion to the influence the Church exerts, the spectacle that everything truly noble is attracted by the Christian faith and the contrary repulsed. In addition the intrinsic grandeur and harmony of the truths of faith, above all the unique figure of Christ, with His wonderful life and sufferings, also the calm and peace of mind effected in the soul of the faithful by living and thinking in this faith; all these tell him that here the spirit of God is breathing, the spirit of truth. The natural light of his intellect, further illuminated by grace, suffices to give him a true intellectual certainty of his faith, based upon these motives and similar ones, even without scientific studies. The calmness of the mind that holds fast to this faith, the compunction and unrest which follow defection from the faith, both so characteristic of Catholics, prove that their minds embrace the truth in their faith. Hence it betrays little philosophical knowledge of the peculiarity of man’s intellectual life, if infidelity approaches an inexperienced, believing student, perhaps even an uneducated labourer, with the express assurance that his faith hitherto has been but a blind belief, an unintelligent following of the lead of a foreign authority, with the distinct admonition to turn his back on the faith of his childhood. What has been said above makes it clear why a Catholic is not permitted to have a serious doubt about his faith under the pretext that he ought first to form a certain conviction all for himself by scientific investigation. He has it already, if we presuppose sufficient instruction and normal conditions; he may raise his natural certitude to a scientific one by study if he has the time and talent for it, but he must not condition his assent upon the success of his scientific investigations. He has certitude; he has no right to demand scientific knowledge as a necessary condition, because it is not required for certitude, and also because it lies altogether outside of the conditions of human life. It would amount simply to shaking off the yoke of truth. The Church teaches as follows: “If any one says that the condition of the faithful and of those who have not yet come to the only true faith is equal, so that Catholics can have a just cause for suspending their assent and calling in question the faith which they have received by the ministry of the Church until they have completed the scientific demonstration of the credibility and truth of it, let him be anathema.”