Catch 22 - do people co-operate or do they compete?

I've just started reading Joseph Heller's Catch 22 again. There's an interesting paragraph on the frontispiece:

"From now on I'm thinking only of me".

Major Danby replied indulgently with a superior smile: "But, Yossarian, suppose everyone felt that way?"

"Then", said Yossarian, "I'd certainly be a damned fool to feel any other way, wouldn't I?"