Since philosophy took its (disastrous) turn into epistemology with Descartes, reinforced by Kant; intelligent people have become 'hung-up' on the fact that they cannot know with certainty that any-thing is absolutely true.
In its most modern form, this is a self-mistrust; the mind experiences that it is its-self too labile and unreliable to know, and stick to, any truth - even if it stumbled upon such a thing.
This mainstream belief is not quite relativism - which asserts explicitly that truth cannot be known, and doing-so falls into the Cretan Liar paradox of asserting as truth that there is no truth. No - the modern relativism is experiential; more like self-doubt, self-mistrust - based on the experienced lability of thinking; an ineradicable subjective uncertainty about the truth of any-thing (whether general or specific).
This 'existenatial doubt' is partly due to the problem of, the impossibility, of communication - as communication is conceptualised by materialistic science; since any such communication involves multiple steps (expression, transmission, reception, decoding, interpreting etc.), and at any stage there is possibility/ near-certainty of a failure of intent to match-up that which is intended with that which eventuates.
Existential doubt is also partly due to our inner knowledge of a change in capacity, as happens during development - the change from child to adult, or alert and fatigued, between healthy and ill - which encompasses our ability to know anything, and how much we can know.
But ultimately, existential doubt is correct but wrongly understood. Correct because knowing is not the primary reality of existence - and that is why the turn to epistemology was an error (because it tries to make knowing the ultimate metaphysical reality)
Existentialism tried to replace knowing with Being as the ultimate reality; but this did not work, because Being is inarticulate - it can only be discussed indirectly, by communications, so that it falls into the same problem.
The correct conception of reality is the Christian one (the Romantic Christian one, specifically; which detaches Christianity from its distorting and paradox-inducing roots in classical philosophy).
The Romantic Christian metaphysically (by assumption) roots reality in love, and understands love to be creative - hence 'dynamic'. Indeed, setting aside these abstractions; it regards created reality as the loving relations between Beings through time.
Not as knowledge, not as Beings in detached, static abstraction - but as a moving, purposive, meaning-full web of relationships.
Within such a world picture it does not make sense to want, or to mourn the absence of, detached abstract chunks of certainty expressible in words or symbols.