I think big "T" Truth may not exist. I think what we call "truth" is something we've found to be such a reliable convention that it would take an amazing discovery to uproot it and change it. Our understanding of gravity, for example, is quite good in that we know what goes up must come down. That said, we still don't know if things such as a graviton exist or if gravity might be something we can manipulate in the future. If we make new discoveries which lead to things like a gravity gun where it could be manipulated at will then calling gravity a big "T" Truth would have been presumptuous and wrong.

I'm comfortable with this definition of truth:

that which is true or in accordance with fact or reality.

When our understanding of facts and reality improve, then our concept of truth will improve along with it. That's why I don't see truth as unchanging as it only represents, at any given time, our current understanding of what "is".

Does that make sense?