“RIGOURSLY speaking, it must be said that, from the objective point of view of the intrinsic nature of the diverse types of knowledge, neither Skepticism, nor Nominalism, nor Pragmatism, nor Positivism, nor Dialectical Materialism nor Existentialism crosses the threshold at which philosophical knowledge starts. From the beginning—an notably in the crucial domain which is the critical reflection on knowledge and in which philosophical wisdom becomes aware of its roots—these systems categorically reject certain primordial truths and original apperceptions which support the noetic structure of philosophical knowledge as such. They are self-destructive philosophies; they punish themselves like the Heautontimorumenos of Terence, because by reason of a defect in their primary assertions they have rendered themselves incapable of arriving a philosophic existence. And naturally, they are not aware of it. They speak much and they say lots of remarkable things, but they are still in a prenatal state.”
~Jacques Maritain: Approaches to God.