Knowledge becomes evil if the aim be not virtuous.

As long as the acquisition of knowledge is rendered habitually repugnant, so long will there be a prevailing tendency to discontinue it when free from the coercion of parents and masters.

Knowledge often spoils devotion.

The medical profession is unconsciously irritated by lay knowledge.

Nothing has more retarded the advancement of learning than the disposition of vulgar minds to ridicule and vilify what they cannot comprehend.

A human being in perfection ought always to preserve a calm and peaceful mind and never to allow passion or a transitory desire to disturb his tranquility. I do not think that the pursuit of knowledge is an exception to this rule. If the study to which you apply yourself has a tendency to weaken your affections and to destroy your taste for those simple pleasures in which no alloy can possibly mix, then that study is certainly unlawful, that is to say, not befitting the human mind. If this rule were always observed; if no man allowed any pursuit whatsoever to interfere with the tranquillity of his domestic affections, Greece had not been enslaved, Caesar would have spared his country, America would have been discovered more gradually, and the empires of Mexico and Peru had not been destroyed.

Beware of the man who works hard to learn something, learns it, and finds himself no wiser than before. He is full of murderous resentment of people who are ignorant without having come by their ignorance the hard way.

Knowledge is dangerous.

Even as a youngster, though, I could not bring myself to believe that if knowledge presented danger, the solution was ignorance.

Calvin: The more you know, the harder it is to take decisive action.
Once you are informed, you start seeing complexities and shades of gray.
You realize nothing is as clear as it first appears. Ultimately, knowledge is paralyzing.
Being a man of action, I cannot afford to take that risk.

Hobbes: You're ignorant, but at least you act on it.

Continual intellectual study results in vanity and the false satisfaction of an undigested knowledge.

The Master said, “Learning without thought is labor lost; thought without learning is perilous.” The Master said, “The study of strange doctrines is injurious indeed!” The Master said, “Yu, shall I teach you what knowledge is? When you know a thing, to hold that you know it; and when you do not know a thing, to allow that you do not know it;-this is knowledge.

For why should the thirst for knowledge be aroused, only to be disappointed and punished?

You should know now that a man of knowledge lives by acting, not by thinking about acting, not by thinking about what he will think when he has finished acting. A man of knowledge chooses a path with heart and follows it. Carlos Castaneda