At the same time the _unprepossession of this science_ will be made clear. “A feeling of degradation pervades the German university circles,” so the learned _Mommsen_ expressed himself some years ago when Strassburg was to get a Catholic chair of history; therefore a Catholic who takes his Catholic view of the world as his guide cannot be unprepossessed, hence cannot be a true scientist. We have become used to this reproach; nevertheless it is very painful to a Catholic, especially when he devotes his life to scientific work. The other side claims very emphatically to have a monopoly on unprepossession and truthfulness; it gives most solemn assurances of not desiring anything but the truth, of serving the truth alone, with persevering unselfishness, unaffected by disposition and party interest, and that it has its unbiassed spiritual eye turned only to the chaste sunlight of truth. Hence, we may be permitted to inquire whether these assurances square with the facts. As they demand belief, we may also demand proofs; and if those assurances are accompanied by sharp accusations, the accused will have even a greater right to examine the deeds and records of this assertive science. What about the unprepossession of liberal science, especially in the province of philosophy and religion? It cannot be our intention to explore the whole territory in every direction. We shall keep to the central and main road, the road to which chiefly lead all other roads of life, we mean the attitude of this school of research towards the world beyond. We find this attitude to be one of persistent ignoring! Science cannot acknowledge the supernatural; this presumption, unproved and impossible of proof, it never loses sight of, it is even made a scientific principle, which is called: The Principle of Exclusive Natural Causation. This principle demands that everything belonging to nature in its widest sense, consequently all objects and events of irrational nature and of human life, must be explained by natural causes only; supernatural factors must not be brought in. To assume an interposition by God, in the form of creation, miracle, or revelation, is unscientific; he who does so is not a true scientist. A presumption, a mandate of truly stupendous enormity! How can it be proved that there is no God, that creation, miracles, the supernatural origin of religion, are impossible things? And if they are possible, why should it be forbidden to make use of them in explaining facts which cannot otherwise be explained? However, it is readily admitted that the principle is merely a postulate, an _unproved_ presumption.