There is no fulfillment in things whatsoever. And I think one of the reasons that depression reigns supreme amongst the rich and famous is some of them thought that maybe those things would bring them happiness. But what in fact does is having a cause having a passion. And that's really what gives life's true meaning.
The duty of man is the same in respect to his own nature as in respect to the nature of all other things namely not to follow it but to amend it.