Again I warn you, beware of philosophers and great reasoners. They will always be a snare to you, and will do you more harm than you will know how to do them good. They linger and pine away in discussing exterior trifles, and never reach the knowledge of the truth. Their curiosity is an insatiable spiritual avarice. They are like those conquerors who ravage the world without possessing it. Solomon, after a deep experience of it, testifies to the vanity of their researches.

—François Fénelon, Spiritual Progress

It is now four months since I have had any leisure for study; but I am very happy to forego study, and not to cling to anything, when providence would take it away. It may be that during the coming winter I shall have leisure for my library, but I shall enter it then, keeping one foot on the threshold, ready to leave it at the slightest intimation. The mind must keep fasts as well as the body. I have no desire to write, or speak, or to be spoken about, or to reason, or to persuade any. I live every day aridly enough, and with certain exterior inconveniences which beset me; but I amuse myself whenever I have an opportunity, if I need recreation.

—François Fénelon, Spiritual Progress

Augustine does not condemn all observation of the natural, but he does condemn seeking knowledge of the created world for its own sake and for the achievement of having understood it, rather than for what it can reveal about its creator.

St. Augustine’s Confessions – Summary and Analysis Book 10: Chapters 26-34

Students and learned men of every kind and every age go as a rule in search of information, not insight. They make it a point of honour to have information about everything: it does not occur to them that information is merely a means towards insight and possesses little or no value in itself. When I see how much these well-informed people know, I sometimes say to myself: Oh, how little such a one must have had to think about, since he has had so much time for reading!

—Arthur Schopenhauer, Essays and Aphorisms (Classics)

To estimate a genius you should not take the mistakes in his productions, or his weaker works, but only those works in which he excels. For even in the realm of the intellect, weakness and absurdity cleave so firmly to human nature that even the most brilliant mind is not always entirely free of them: whence the mighty errors which can be pointed to even in the works of the greatest men,

—Arthur Schopenhauer, Essays and Aphorisms (Classics)

A little philosophy leads away from God, a lot of it leads back to him..

—Arthur Schopenhauer, Essays and Aphorisms (Classics)

Thinkers can be divided into those who think in the first instance for their own instruction and those who do so for the instruction of others. The former are genuine thinkers for themselves in both senses of the words: they are the true philosophers. They alone are in earnest. The pleasure and happiness of their existence consists in thinking. The latter are sophists: they want to appear as thinkers and seek their happiness in what they hope thereby to get from others. This is what they are in earnest about. To which of these two classes a man belongs may quickly be seen by his whole style and manner.

—Arthur Schopenhauer, Essays and Aphorisms (Classics)

People who pass their lives in reading and acquire their wisdom from books are like those who learn about a country from travel descriptions: they can impart information about a great number of things, but at bottom they possess no connected, clear, thorough knowledge of what the country is like. On the other hand, people who pass their lives in thinking are like those who have visited the country themselves: they alone are really familiar with it, possess connected knowledge of it and are truly at home in it.

—Arthur Schopenhauer, Essays and Aphorisms (Classics)