It doesnt matter whether they are at great elevation or at sea level. John Geiger suggests that the brains effort to create a Third Man is not an accident of human brain structure, or a sign of injury in extreme conditions.

VOA: special.2010.02.24

And our third example touches on not when you are expressing a level of certainty,

接下来的第三个例句并不是用于表示某种程度的肯定，

I'm sure 课堂 - SpeakingMax英语口语达人