Here we have the infallible kind of Sign, the only kind that constitutes a complete proof, since it is the only kind that, if the particular statement is true, is irrefutable.

这样我们就有了绝对可靠的迹象，唯一构成完全论据的那种，因为只有这种迹象在陈述为真时不会被驳倒。

youdao

The irrefutable proof of excess demand is that universities pay legions of employees to turn down perfectly good business.

FORBES: School For Scandal