* Mean is a mathematical concept: Means are calculated for sets of numbers. "Truth" and "world" are abstract concepts, not numbers.
* The phrase is a statement, not data: The phrase expresses a philosophical or moral idea, not a collection of measurable data.
What the phrase means:
The phrase likely conveys the idea that the truth, even if it's difficult or unpopular, is more important than any other worldly concerns. It suggests that upholding truth is a higher value than conforming to social norms or seeking personal advantage.