You can construct "truths" in a abstract system such as logic or mathematics. For example: A->B, B->C => A->C or 2+2=4. But those truths rely on a bunch of definitions and assumptions about the abstract system.
I would agree that you can't define (or point out) absolute truths in the physical world - at least not if you use the conventional scientific model of the world.
Whether or not absolute truths exists in the spiritual/divine domain is an interesting question.
Rasmus