Methaphysical problems have two characteristics: they are unreachable by science, and they are not susceptible of solution, even by reasoning.

How many of these problems are there? This is very uncertain. In any case the following may be considered as such:

1. Eternity or not‑eternity of the universe.

2. The problem of the Universals.

3. The immortality of the soul.

(Free‑will I consider, with Haeckel, not to be an object for critical inquiry, but to be a pure illusion.)

Problems of metaphysics:

Secondary ontological problem: the nature of the world.

Secondary problem: the problem of the universals.

Secondary moral problem: the problem of the origin of values.

(Nietzsche more or less).

Problem of the Universals.

Problem of Attributes.

Problem of non‑relative relation.

() — What is the relation, if any, between Being and the world? How does the world exist?

() — Is the world eternal and infinite, or limited, in space and in time? In what manner does the world exist ?

() — Problem of the future or of destiny. Why does the world exist?

Applying to the world the 3 ideas: Cause, Thing, End.