Exactly: this is the radical problem of metaphysics: it doesn’t draw the consequences of its own statements, it doesn’t follow its own methods, its own procedures, preferring, instead, to stop in the middle of the reasoning. This is what happens:
1) metaphysics make statements that are universal, or we can say “a priori”, such as
1) there is.
2) There is something.
3) Change is something. — Xtrix
2) Since they are a priori, universal, they must be able to take into account everything, they must be able to face any other consideration.
3) Taking into account everything means taking into account also the consideration that all the statements have been made by using a brain, a human mind, we can call it “subjectivity”.
4) The consequence of taking into account the subjectivity that has been inevitably involved to produce the statements is that the statements cease to be universal, because they are implicated in the non universality of subjectivity.
5) The conclusion is that kind of reasoning:
- if something is universal, it must be able to take into account subjectivity
- taking into account subjectivity creates the consequence that it is not universal
In other words: if something is universal, then it is not universal.
Even in shorter way: if being is, then it is not.
This is the radical contradiction that metaphysics tries to avoid, because it is too disturbing, too uncomfortable, destabilizing, not reassuring at all.
I have just described in a structured way what has already been noticed by Heidegger, nothing new.
But he went on with the idea of changing the meaning of metaphysics, keeping himself in the mental frame of “being” and forcing the meaning of “being” into a human context, implicated in time and death, while instead I, like postmodern philosophy does, consider clearer to admit that metaphysics is just contradictory, as well as the concept of “being”, as well as Parmenide’s principle of non contradiction.