To every action there is always an equal and opposite or contrary, reaction

If you're teaching today what you were teaching five years ago, either the field is dead or you are.

Any man who reads too much and uses his own brain too little falls into lazy habits of thinking.

A child educated only at school is an uneducated child.

I am a part of everything that I have read.

The knowledge of all things is possible

I decided to teach because I think that any person who studies philosophy has to be involved actively.

No power and no treasure can outweigh the extension of our knowledge.

Any knowledge that doesn't lead to new questions quickly dies out: it fails to maintain the temperature required for sustaining life.

Knowing others is wisdom, knowing yourself is Enlightenment.

It is better to know how to learn than to know.

I learned very early the difference between knowing the name of something and knowing something.

Better know nothing than half-know many things.

Common sense is the collection of prejudices acquired by age eighteen.

The only good is knowledge and the only evil is ignorance.

God created man in His own image, says the Bible; philosophers reverse the process: they create God in theirs.

Reading without reflecting is like eating without digesting.

My alma mater was books, a good library.... I could spend the rest of my life reading, just satisfying my curiosity.

The delight of opening a new pursuit, or a new course of reading, imparts the vivacity and novelty of youth even to old age.

Books are as useful to a stupid person as a mirror is useful to a blind person.

Real knowledge is to know the extent of one's ignorance.