She just gave me a sharp, haughty look, but her expression did nothing to hide one simple, irreducible fact.

And Kane informs us, quite casually, "one irreducible fact is that people who climb mountains are invariably cunts".

Amid all these fantasies and equivocations, however, there were two irreducible facts: death and Judith.

The controversy around his action, which saw him wrongly accused of being a "chucker", has long since been obliterated by the irreducible facts.