Single word that means something cannot be disproven?

In the same way unprovable means that something cannot be proven.

E.g. solipsism would be able to be described with this, because it's perfectly logical and infallible.

A synonym of this word may be infallible, but infallible is too strong. Infallible connotes too strongly "absolute."

Solipsism is undisprovable.

  • You seem to have worked your way into a logical muddle: Some statement is provable or not provable. An argument is fallacious and people are fallible. One would use the negative: an argument is disprovable or an argument in not disprovable. Undisprovable sounds, and is, indisputably awful.
    – Lambie
    Commented Dec 17, 2017 at 19:12
  • 2
    'untestable'?. Did you look in a thesaurus around all these?
    – Mitch
    Commented Dec 17, 2017 at 19:29
  • It's just tricky because while these are all correct ways of describing things like this, e.g. untestable, I want a word that connotes "is logically true but not necessarily true"
    – minseong
    Commented Dec 17, 2017 at 20:40
  • 1
    Uh… what did your favourite dictionaries, thesauruses and search engines not tell you, please? Never you mind no solipsism; the term for something which cannot be disproven would be undisprovable, would it not? Commented Dec 18, 2017 at 23:05
  • 1
    @theonlygusti logically true is usually considered identical to necessarily true with respect to any context. So you can't have one without the other. And now we move into either philosophy or math. You could say 'irrefutable' because it is something that is not refutable but it is also not provable which is usually not what is meant by 'irrefutable'. On the math side, you can say that solipsism is undecidable (it is neither provable nor disprovable from given data). But that is a technical use of 'undecidable' so may not work for your audience.
    – Mitch
    Commented Dec 19, 2017 at 1:12

2 Answers 2


Unfalsifiable might work:

not capable of being proved false

(definition from Merriam-Webster)


Non-disprovable (used in logic discussions) or undisprovable (as per http://www.dictionary.com/browse/disprovable) seems acceptable.

As indicated in the comments, it refers to specific situations where a hypothesis cannot be tested or in general cannot be disproven by any scientific method, etc.

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