“Truth used to be based on reason.”
J.P.Moreland, Introduction to
Escape From Reason 2006
by Francis A. Schaeffer

Etymologically speaking, reason comes from ratio.
‘Reason’ in Latin but also having to do with ‘reckoning’.
With dividing the ‘big picture’ into easier to understandable slivers. Slivers meant to be analyzed and later assembled back into meaning. Into ‘truth’.

Currently we understand reason as “the intellectual faculty that adopts actions to ends“.

Now, which of the two reasons gives birth to the ‘genuine’ truth?

The analytical/synthetic one which attempts to develop reality into meaning or the one which defends and embellishes the already known truth? The revealed truth?

The whole thing depends on the “ends” of the reasoning agent?

Reason, hence truth, depends on the intention of the individual performing the act of reasoning?!?

Quite unreasonable, don’t you think?
Truth was supposed to be anchored in reality, right?!? Not on ‘intention’….

Truth as unhiddenness… is a concept developed by Heidegger.
Basically, this whole thing is about individuals being unable to discover nor formulate the ‘entire’ truth so a ‘bigger’ truth may be reached only through cooperation. Everybody ‘says’ – unhides – everything they know about a subject and that’s how the most complete truth available at that moment is ‘uncovered’.

‘But this means the Truth becomes fluid.
No longer ‘fixed’. Unreliable!’

I’m afraid you’re right!
Except for the ‘unreliable’ part.
As long as enough people do their part, and honestly speak up their minds, the most reliable truth knowable at any given moment will become apparent to everybody.
To everybody who cares to look for it!
To everybody who accepts that their reason, while imperfect, can and should contribute to the common effort to get closer to truth.
To everybody who accepts that other people’s reason, while imperfect, can and should be listened to in the common effort to get closer to truth.
To everybody who accepts to continue this effort knowing very well that no matter how hard they will try, people will never find the entire truth