2 Whoso turns his attention to the bitter strifes of these days and seeks a reason for the troubles that vex public and private life must come to the conclusion that a fruitful cause of the evils which now afflict, as well as those which threaten, us lies in this: that false conclusions concerning divine and human things, which originated in the schools of philosophy, have now crept into all the orders of the State, and have been accepted by the common consent of the masses. For, since it is in the very nature of man to follow the guide of reason in his actions, if his intellect sins at all his will soon follows; and thus it happens that false opinions, whose seat is in the understanding, influence human actions and pervert them. Whereas, on the other hand, if men be of sound mind and take their stand on true and solid principles, there will result a vast amount of benefits for the public and private good. We do not, indeed, attribute such force and authority to philosophy as to esteem it equal to the task of combating and rooting out all errors; for, when the Christian religion was first constituted, it came upon earth to restore it to its primeval dignity by the admirable light of faith, diffused "not by persuasive words of human wisdom, but in the manifestation of spirit and of power",(3) so also at the present time we look above all things to the powerful help of Almighty God to bring back to a right understanding the minds of man and dispel the darkness of error.(4) But the natural helps with which the grace of the divine wisdom, strongly and sweetly disposing all things, has supplied the human race are neither to be despised nor neglected, chief among which is evidently the right use of philosophy. For, not in vain did God set the light of reason in the human mind; and so far is the super-added light of faith from extinguishing or lessening the power of the intelligence that it completes it rather, and by adding to its strength renders it capable of greater things.
Source: Aeterni Patris (Vatican.va)