Acceptance of a worldview or memeticity on faith or trust, without critical intellectual analysis.
Often any structured or even halfway-credible set of memetics, such as a religion or philosophy, will find followers and also disbelievers, mostly amongst the beings of normal human intelligence and those slightly augmented. However many sentients of advanced mental development take a very rigorous attitude to belief, and faith, and scientific proof.
Posthumans and very high superbrights often have completely different belief systems, and as you move into beings that are past the first or second singularity level(s), they are often capable of believing and juggling many contradictory concepts with little effort or paradox from their own understanding.
While many forms of materialism remain current among the augmented, there are also some superbright societies that have concentrated on the apparently ridiculous, like the Equivocalists and Dissemblers who use their superior mental ability to attempt to live in completely unworkable societies, following thousands of years of rationalist society which developed into a decadent or experimental form.
Another reason for nonmaterialist beliefs to develop in a rational society is the constant transcendence of the most advanced individuals. If the mental shape (toposophy) of a newly transcended individual is very different, eir old colleagues or family or lovers will look on with wonder and sometimes resentment, and any number of irrational effects may occur in even a superbright society.
Transcended individuals and Gods sometimes even introduce religious or philosophical memetics as social experiments or obscure jokes.