The rationalist believes in the use of reason rather than experience of spiritual revelation and sense experience to define knowledge. The use of rational methods may not be successful for understanding much in the life of the spirit and in human history (such as subconscious processes of the human mind), and therefore it is a limited instrument of knowledge.
Attributes to natural reason a knowledge which only the light of faith could confer. (Papal Encyclical, Laborem Exercens, 14 September 1981).
There exists no Supreme, all-wise, all-provident Divine Being, distinct from the universe, and God is identical with the nature of things, and is, therefore, subject to changes. In effect, God is produced in man and in the world, and all things are God and have the very substance of God, and God is one and the same thing with the world, and, therefore, spirit with matter, necessity with liberty, good with evil, justice with injustice. (Papal Allocution Maxima Quidem, 9 June 1862).