Truth is about what is firm and essential on earth. What is unchangeable is the mystery of the earth. The truth is part of the mystery, or; the mystery is part of the revelation of eternal truth. For instance, the revelation of Pythagorean theorem. By turning the truth away from the firm and essential, we have turned the truth against the mystery of the earth.
The scientific understandig of truth removes the phenomenon from the mystery of the earth, away from revelation and the eternal. The truth is left to describe the changing earth, expressed as probabilities. It is this kind of truth Cioran calls boaring.
Of all times, human as expressed a lot of belives, but not many truths. As more we express, the more infrequent the truth may apear.