indemonstrably

/ɪnˈdɛmənstrəbli/
adverb
  1. In a way that cannot be proven or shown to be true.
    • The theory was indemonstrably false, but he still believed it.
    • She argued indemonstrably that the ancient artifact had magical powers.
    • Some philosophical claims are indemonstrably true by their very nature.
Antonyms
What does "indemonstrably" mean? | whatsthatwordmean | whatsthatwordmean