Authors:

In order to judge of the inside of others, study your own; for men in general are very much alike; and though one has one prevailing passion, and another has another, yet their operations are much the same; and whatever engages or disgusts, pleases or offends you, in others, will, mutatis mutandis, engage, disgust, please, or offend others, in you.

"Manners and speech or maxims extracted from Lord Chesterfield's letters to his son". Book by Lord Chesterfield, 1884.
In order to judge of the inside of others, study your own; for men in general are very much alike; and though one has one prevailing passion, and another has another, yet their operations are much the same; and whatever