Excerpts from "Don't Sleep There Are Snakes" by Daniel Everett

The [Pirahas] made it clear that if I had not actually seen this guy [Jesus] (and not in any metaphorical sense, but literally), they weren't interested in any stories I  had to tell about him.  Period.  This is because, as I now knew, the Pirahas believe only what they see.

. . . . .

Their [Pirahas] own beliefs were not in the fantastic and miraculous but in spirits that were in fact creatures that did normal kinds of things (whether or not I thought they were real).  There was no sense of sin among the Pirahas, no need to "fix" mankind or even themselves.  There was acceptance for things the way they are, by and large.  No fear of death.  Their faith was in themselves.  

. . . . .

They [Pirahas] don't believe in heaven above us, or a hell below us, or that any abstract cause is worth dying for.

...they have independently discovered the usefulness of living one day at a time.  The Pirahas simply make the immediate their focus of concentration, and thereby, at a single stroke, they eliminate huge sources of worry, fear, and despair that plague so many of us in Western societies.

Truth to the Pirahas is catching a fish, rowing a canoe, laughing with your children, loving your brother, dying of malaria.