There is a direct, feeling-based, non-rational way of thinking which Robert Graves termed analeptic and proleptic thinking- analeptic thinking is a vision of the past while proleptic refers to the future.
This happens in what could be termed a trance state, a state of altered consciousness, somewhat detached from immediacy and distraction - in which some other time or place (or person) or even an idea (a concept, an image, a belief) is perceived and felt as real.
What does this mean?
I think when something is analeptic/ proleptic it means that there is a certain validity and coherence to an idea. It does not mean that it is true - but it means that it is... well, that it is worth considering, worth thinking-about at least.
So, when something appears through analeptic thinking it then needs to be validated in whatever ways appropriate - by logical analysis, experience, new observations and so on.
But there is more to it than this; I think intuition is necessary to truth - for it to be meaningful, purposive truth.
Truth is contained-within intuition.
If you don't have an intuition, a personal sense of the reality of a time, place, person, idea, vision, notion... then it cannot be really real.
So, to evaluate an idea that is just an idea - then there must be a process of seeking intuitive confirmation; and unless or until the idea is confirmed by intuition (analeptic or proleptic thought) then it is not rally real and not much use could or should be made of it.