(n.) The quality or state of being irrefragable; incapability of being refuted.

accomplished fact achievement actualization attainment authenticity basis being confirmability demonstratability doubtlessness embodiment essence eternal verities externalization fact factuality fait accompli good sooth grim reality historical truth historicity incarnation incontestability incontrovertibility indisputability indubitability indubitableness irrefragability irrefutability materialization not a dream objective existence provability questionlessness reality sooth substance the true trueness truth truthfulness ultimate truth unconfutability undeniability unerroneousness unfallaciousness unfalseness unimpeachability unquestionability unrefutability veracity verifiability verity very truth