It is well known that a number of doctrinal decisions on philosophical topics have been promulgated by the reigning Sovereign Pontiff, which have made the true sense and teaching of the church on several important points much more clear and definite than it had previously been to a large number of sincere and learned Catholics. For a long time, some of these decisions—those, namely, concerning ontologism—were not universally known, and their import had not been sufficiently discussed and explained to give a certain and distinct direction to those who, like ourselves, in this country, had not been _au courant_ with the affairs which brought about these decisions. Philosophy has been generally, and more especially in England and the United States, in a miserable and chaotic state until a comparatively brief period, during which a more wholesome tendency has been awakened. The worst and most dangerous errors have been those which have sprung from the sensist school. As a natural consequence, those whose Catholic belief has led them to reject these gross errors, being unacquainted with the scholastic philosophy, have been inclined to throw themselves back on Platonism, and to welcome any system of philosophy which put forward a high ideological doctrine in which the necessary and eternal truths, the immutable principles of first and final cause, the being and attributes of God, and all natural theology, were professedly exalted to their due supremacy, and placed on a basis unassailable by a mean scepticism and materialism. The very same took place in the instance of Cardinal Gerdil, of Malebranche, and of others, at a former period; and F. Ramière, one of the most successful opponents of ontologism, has lucidly explained how this is precisely the reason that the said system has appeared in a captivating light, in our own day, to a number of minds to which scepticism and materialism are especially odious. This may explain the fact that we have taken a more decisive and explicit stand in regard to several important philosophical doctrines, since the more thorough examination of the differences between the ancient and received teaching of Catholic schools, and the various modern theories, have convinced us of the great importance of adhering closely, not only in respect to the substance of doctrine, but even in respect to form and the use of terms, to that philosophy which has a Catholic sanction. Within the limits defined by positive, explicit authority, this adhesion is, of course, obligatory on the conscience in the strictest and gravest sense. In a former article on Dr. Stöckl’s _Philosophy_, we have explained our position, which is that of the best and most approved European authors, in regard to this obligatory doctrine, so far as relates to ideology. Beyond this, we respect, of course, the liberty which the church concedes. Her positive sanction has been given to the scholastic principles, method, and doctrine, only in general terms.