A while back I received a comment regarding the difference between metaphysical and logical absolutes. I think there is an important point to be made here.
The most obvious kind of absolute truth is that which branches from the natural world such as science and mathematics. We can absolutely know things like 2+2=4 and the like. But what about things of a more abstract, metaphysical nature?
If we assert anything to be true at all, that truth by definition must be absolute. If a truth is not absolute, then it is no truth at all, but merely subjective opinion. But if a truth is really true, then it must be absolute and unchanging. This does not change, regardless if the truth in question is scientific or metaphysical.