The Ultimate Truth is that there is no ultimate truth. Where does that leave your assumed facts?
Basic logic error there: assumptions are not facts. Assumptions are assumptions; facts are facts. The two are not the same.
It leaves me with ordinary truths, not ultimate truths. I can work well enough with ordinary truths; ultimate truths are unnecessary and more of a distraction than anything.
The parable of truth goes something like this...
When truth was born, it was visited by a magical fairy and blessed with three qualities: the ability to be absolute, the ability to be objective, and the ability to refer to the external world. The condition for this blessing was that truth could only exhibit a maximum of two of those qualities simultaneously. Therefore it could be absolute and objective, but not refer to the external world (mathematical truth). It could be objective and refer to the external world, but not absolute (scientific truth). Finally, it could be absolute and refer to the external world, but not objective (aesthetic truth).
We need to use the correct type of truth for whatever topic we are working on.