The question is "whether truth is of any value or not, or is it sufficient to have something truthful enough to work with?"
I mean, so the Earth goes around the Sun... now what?
Well we use the little truths we find, the knowledge, in many ways. Because we know that the earth goes around the sun, we can calculate how to throw something and have it hit the intended target. That in turn lets us go out and determine the composition of comets and asteroids and those in turn tell us more about the earth we live on, maybe even ultimately about how we became we.
What do we do with all of this 'truthful reality' that we suddenly 'know'?
What we do with all the "truthful realities" is use them as stepping stones to learn more about how things work, and learning how things work is the first step in learning how to make them work as we would like.
Personally, I would say that one Josiah Wedgwood is worth 50 or 100 Platos.
Aslan is not a
Tame Lion