from Leviathan

chapter 6

Continual success in obtaining those things which a man from time to time desireth, that is to say, continual prospering, is that men call felicity; I mean the felicity of this life. For there is no such thing as perpetual tranquility of mind, while we live here; because life itself is but motion, and can never be without desire, nor without fear, no more than without sense. What kind of felicity God hath ordained to them that devoutly honour Him, a man shall no sooner know than enjoy; being joys that now are as incomprehensible as the word of School-men, beatifical vision, is unintelligible. 

chapter 11

By manners, I mean not here decency of behaviour; as how one man should salute another, or how a man should wash his mouth, or pick his teeth before company, and such other points of the small morals; but those qualities of mankind that concern their living together in peace and unity. To which end we are to consider that the felicity of this life consisteth not in the repose of a mind satisfied. For there is no such finis ultimus (utmost aim) nor summum bonum (greatest good) as is spoken of in the books of the old moral philosophers. Nor can a man any more live whose desires are at an end than he whose senses and imaginations are at a stand. Felicity is a continual progress of the desire from one object to another, the attaining of the former being still but the way to the latter. The cause whereof is that the object of man's desire is not to enjoy once only, and for one instant of time, but to assure forever the way of his future desire. And therefore the voluntary actions and inclinations of all men tend not only to the procuring, but also to the assuring of a contented life, and differ only in the way, which ariseth partly from the diversity of passions in diverse men, and partly from the difference of the knowledge or opinion each one has of the causes which produce the effect desired. 

- Thomas Hobbes (1588-1679)