We are here just for a spell and then pass on … So get a few laughs and do the best you can. Live your life so that whenever you lose, you are ahead.

Will Rogers (1879-1935) American humorist

Inscription, Oklahoma Route 66 Museum, Clinton, Oklahoma

This appears to be condensed form of one of his Weekly Article columns (1931-06-28), collected in Donald Day (ed.), The Autobiography of Will Rogers, ch. 16 (1948), where he responds to Will Durant's request to him (and others) to write about his Philosophy of Life (emphasis mine):

What all of us know put together dont mean anything. Nothing dont mean anything. We are just here for a spell and pass on. Any man that thinks that Civilization has advanced is an egotist. Fords and bathtubs have moved you and cleaned you, but you was just as ignorant when you got there. We know lots of things we used to dident know but we dont know any way to prevent em happening. Confucius perspired out more knowledge than the U.S. Senate has vocalized out in the last 50 years.
We have got more tooth paste on the market, and more misery in our Courts than at any time in our existence. There aint nothing to life but satisfaction. If you want to ship off fat beef cattle at the end of their existence, you got to have em satisfied on the range. Indians and primitive races were the highest civilized, because they were more satisfied, and they depended less on each other, and took less from each other. We couldent live a day without depending on everybody. So our civilization has given us no Liberty or Independence.
Suppose the other Guy quits feeding us. The whole thing is a "Racket," so get a few laughs, do the best you can, take nothing serious, for nothing is certainly depending on this generation. Each one lives in spite of the previous one and not because of it. And dont start “seeking knowledge” for the more you seek the nearer the “Booby Hatch” you get. And dont have an ideal to work for. Thats like riding towards a Mirage of a lake. When you get there it aint there. Believe in something for another World, but dont be too set on what it is, and then you wont start out that life with a disappointment. Live your life so that whenever you lose, you are ahead.