The busier we are, the more acutely we feel that we live, the more conscious we are of life.

Manners or etiquette ('accessibility, affability, politeness, refinement, propriety, courtesy, and ingratiating and captivating behavior') call for no large measure of moral determination and cannot, therefore, be reckoned as virtues. Even though manners are no virtues, they are a means of developing virtue.... The more we refine the crude elements in our nature, the more we improve our humanity and the more capable it grows of feeling the driving force of virtuous principles.

Always regard every man as an end in himself, and never use him merely as a means to your ends [i.e., respect that each person has a life and purpose that is their own; do not treat people as objects to be exploited].

It is precisely in knowing its limits that philosophy consists.

It is difficult for the isolated individual to work himself out of the immaturity which has become almost natural for him.

We can never, even by the strictest examination, get completely behind the secret springs of action.

Every human being should always be treated as an end and never as a mere instrument.