Self-evidently synonyms

It is of course always possible that in any particular case we may be deceived; we may be assuming as self-evidently true what is in reality not so.

He speaks in a deep-voiced monotone, but he is not perfunctory in his replies or self-evidently bored, as other players can be.

Simply, because to do so would immediately expose his claim to be utterly preposterous and self-evidently false.