They define something special in human nature. They give us a measure of what's possible and what's truly sensational or phenomenal.

All of us have a theory about human nature.

Never literary attempt was more unfortunate than my Treatise of Human Nature. It fell dead-born from the press.

His works (taken together) are almost like a new edition of human nature.

There is a hearty Puritanism in the view of human nature which pervades the instrument of 1787 It is the work of men who believed in original sin, and were resolved to leave open for transgressors no door which they could possibly shut.

You know, it's almost human nature. If you give me a gift, I feel indebted to you... assuming it's a substantial gift.