When a thoughtful human being has overcome incentives to vice and is aware of having done his bitter duty, he finds himself in a state that could be called happiness, a state of contentment and peace of mind in which virtue is its own reward.

[R]eason is... given to us as a practical faculty, that is, as one that influences the will.

Freedom in the practical sense is the independence of the power of choice from necessitation by impulses of sensibility

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].

The death of dogma is the birth of morality.

The only thing permanent is change.

We are not rich by what we possess but by what we can do without.