Archbishop Ullathorne illustrates the differences between knowledge gleaned from books and knowledge obtained through introspection:
“There are many people who read expositions of the virtues in books, and have a real desire to profit by them; yet the knowledge they gain is but little compared with what they might obtain, because they look more into the book than into themselves. They do not reflect upon their own interior state, or upon their own interior operations (in doing which the book is intended to assist them), nor do they carefully observe what passes within their souls. Their knowledge is book-knowledge, not self-knowledge, and is consequently shallow, without roots within them, and quickly fades and passes away. Such unreflecting readers are like the man who beholds his face in a glass, goes his way, and presently forgets what manner of man he is.”
“But if we look upon a book as no more than a help to self-knowledge and the perfecting of the virtues, and if we second the book by interior reflection and observation, then it will enable us to read and understand the interior book of the soul, which has the immense advantage of being illuminated with spiritual light; and we shall thus obtain a knowledge all our own, a true and lasting possession always ready to do us service.”
But, a word of caution: “Self-knowledge is invaluable; yet it is not obtained by peering into our own darkness, but by seeing ourselves as we are reflected in the divine light.” (Christian Patience)
Ullathorne warns of the danger of self-deception: “Who has not known persons who are always in trouble, but never in the wrong?” (Endowments of Man)
Also, he warns of a deleterious effect of pride: “Self-elevation rebounds into self-degradation.” (Groundwork of Christian Virtues)
Finally, he reminds us to fix our gaze firmly upon immutable truth: “Be it ever remembered that truth is the oldest of all things, whilst man is both new and fond of novelties.” (Endowments of Man)
Quotations from Michael F. Glancey, Characteristics From the Writings of Archbishop Ullathorne (London: Burns & Oates, 1889).