Rationalism is a certain abuse of Reason; that is, a use of it for purposes for which it never was intended, and is unfitted. To rationalize in matters of Revelation is to make our reason the standard and measure of the doctrines revealed; to stipulate that those doctrines should be such as to carry with them their own justification; to reject them, if they come in collision with our existing opinions or habits of thought, or are with difficulty harmonized with our existing stock of knowledge. And thus a rationalistic spirit is the antagonist of Faith; for Faith is, in its very nature, the acceptance of what our reason cannot reach, simply and absolutely upon testimony.
--Cardinal John Henry Newman
