Daring adventurers may undertake them. The lecturer at college, too, will be readily pardoned for his eagerness to take up the cudgel in defence of what is new in his profane science: he may easily correct himself. But the Teacher of the Centuries and of the Nations, in the sphere of religion and morals, has not the right to experiment. Here, where mistakes may entail the direst consequences, the rule must be: slowly onward, to keep the whole from ruin. Cardinal _Benedict Gaetani_, later Pope _Boniface VIII._, once praised Rome for having _pedes non plumeos sed plumbeos_—not winged feet, but leaden heels. Sentiments of the kind just set forth are of course possible only in conjunction with the belief in a revelation and in the supernatural character of the Church, where the interests of faith come first, and must be unconditionally preserved. He who lacks this conviction, he to whom the Church is but a human institution, founded in the course of time, tending perhaps to oppose truth and science for fear they might endanger the submission of minds—to such a one the Catholic’s confident devotion to his Church, and consciousness of unimpaired freedom at the same time, will be unintelligible; and the inflexibility of the Church in defending the faith will pass his comprehension. And woe to the Church when her position toward science is being tried before this court: only harsh denunciations are to be expected where the judge does not understand the matter he undertakes to decide. Nor do we attempt to bridge the chasm that separates the two views of the world which we here again encounter, the one, which rejects the supernatural world, the other, the view of the believing Christian. We have but endeavoured to show that _faith does not restrain the mental freedom of one who is convinced of the truth of his faith_. Submission to the authority of faith is the consequence of his conviction. This is the question to be decided: Either there is a revelation and a Church founded by God, or there is not. If such there be, or if it is only possible, then modern freedom of thought, with its demand of exemption from all authority, is against reason and morality. If there is not, then this should be proved. It can be done consistently only by acknowledging atheism. For if there is a personal God, then He can give a revelation and found a Church, and demand submission from all. Since the days of _Celsus_ to this day the attempt to demonstrate that the convictions of a faithful Christian are unjustifiable has proved futile. Obedience of Faith and Injury to Science. While all this is true, yet one may not share this conviction, nor rise to the certainty that there is a supernatural world whence the Son of God descended to teach man and to found an infallible Church. Still, to be fair, he must admit that no real danger to freedom of research and progress of science results from submission to faith, as shown above.