I am content in my later years. I have kept my good humor and take neither myself nor the next person seriously.

The most valuable thing a teacher can impart to children is not knowledge and understanding per se but a longing for knowledge and understanding, and an appreciation for intellectual values, whether they be artistic, scientific, or moral. It is the supreme art of the teacher to awaken joy in creative expression and knowledge. Most teachers waste their time by asking questions that are intended to discover what a pupil does not know, whereas the true art of questioning is to discover what the pupil does know or is capable of knowing.

A person starts to live when he can live outside himself.

The field is the sole influence of the particle.

It is also a natural thing for a serious young man that he should form for himself as precise an idea as possible of the goal of his desires.

I refuse to engage in an intellectual battle with an unarmed man.

To know what is impenetrable to us really exists, manifesting itself as the highest wisdom and the most radiant beauty... this knowledge, this feeling is at the center of true religiousness.