If we pass on from the moral to the intellectual causes of Modernism, the first and the chief which presents itself is ignorance. Yes, these very Modernists who seek to be esteemed as Doctors of the Church, who speak so loftily of modern philosophy and show such contempt for scholasticism, have embraced the one with all its false glamour, precisely because their ignorance of the other has left them without the means of being able to recognize confusion of thought and to refute sophistry. Their whole system, containing as it does errors so many and so great, has been born of the union between faith and false philosophy.
Would that they had but displayed less zeal and energy in propagating it! But such is their activity and such their unwearying labor on behalf of their cause, that one cannot but be pained to see them waste such energy in endeavoring to ruin the Church when they might have been of such service to her had their efforts been better directed. Their artifices to delude men’s minds are of two kinds, the first to remove obstacles from their path, the second to devise and apply actively and patiently every resource that can serve their purpose. They recognize that the three chief difficulties which stand in their way are the scholastic method of philosophy, the authority and tradition of the Fathers, and the magisterium of the Church, and on these they wage unrelenting war. – from Pascendi Domenici Gregis (1907)