There is a natural, inbuilt, spontaneous knowledge of the nature of the world: that the world consists of Life and Reality.
Life is this world: the world of change, of growth and decay and transformation.
Reality is another and less obvious world: eternal and unchanging and the source of knowledge.
From this metaphysic of Life and Reality; arise all questions, all philosophy and all religions.
Questions such as the relation between Life and Reality: why are things set-up this way?
What things are eternal and changeless, what are ephemeral?
Why don't Life and Reality coincide? Or, if they do, why is this not obvious - why is the relationship not spontaneously felt?
What can Life know of Reality, and how?
What is Life for?
And so on.
It is the denial of this knowledge of Life and Reality - denial of the basis of all human thought - that has un-moored modernity and led to endemic insanity.
For modern man, there is only Life and no Reality. Only change and no eternity. Reality is an illusion, there is no source of knowledge, there is no knowledge - there is only growth, decay and transformation.
To believe this is insane, because it makes no sense - worse, it violates sense.
Denying the basis of all philosophy and religion, modern man is unable to reason.
(This applies especially to the most educated intellectuals).