There is no such thing on earth as an uninteresting subject; the only thing that can exist is an uninterested person
The marketplace obliges men, whether they will or not, in pursuing their own selfish interests, to connect the general good with their own individual success
Man acts from adequate motives relative to his interest, and not on metaphysical speculations
Anything becomes interesting if you look at it long enough
Men are moved by two levers only: fear and self interest
A man will fight harder for his interests than for his rights
We are interested in others when they are interested in us
The virtues and vices are all put in motion by interest


On Anger: "For every minute you remain angry, you give up sixty seconds of peace of mind."
On Destiny: "Our destiny exercises its influence over us even when, as yet, we have not learned its nature: it is our future that lays down the law of our today."
Human, All Too Human
On Friendship: "A crowd is not company; and faces are but a gallery of pictures; and talk but a tinkling cymbal, where there is no love."