The basis for philosophy is a recognition that there must be that which is eternal and unchanging for there to be knowledge.
If everything changes and nothing lasts, if everything is the world gets different, then there can be no knowledge: all is swept away.
This metaphysical fact was never controversial until modern times, although the specific nature of the eternal and unchanging was subject to great dispute.
But moderns have lost the ability to perceive this basic rational necessity - I certainly did.
The necessity for the eternal and unchanging (E & U) for any kind of knowledge has been psychologized into a pathological - but unnecessary - compulsion to seek or to claim the eternal and unchanging - usually (it is said or implied) in order to control people.
In sum, the perennial recognition of the necessity for the E & U has been made into a psychological disease characteristic of right wing politics.
Modern philosophy has become pseudo-therapeutic: it tries to treat the recognition of the E & U as a symptom of authoritarianism.
And modern philosophers have lost the ability to perceive that the E & U is a pre-requisite for all and any philosophy, or discourse of every type. They simply can't see this any more.
The door is wedged open to infinite error and nonsense - which has duly come rushing-in.