The indetermination of the most universal principles is - in the exposition of the metaphysical doctrines - cause for rather great difficulties, and often one is forced to use only expressions which are purely negative, of what ”it” is NOT.
A note of capital importance
Not only can metaphysics not be limited to the consideration of any complementary aspects of Being, may it concern those very special aspects such as the soul (mind) and matter, or on the contrary those aspects [which are] as universal as possible, such as those which could be designated by the terms "essence" and "substance", but metaphysics can never be limited by the concept of pure Being [even] in all its universality, because it may not be [limited] by absolutely anything. Metaphysics cannot be defined as "the knowledge of being" in an exclusive way as did Aristotle: then it is but ontology, which without doubt belongs to [a section of] metaphysics, but which for that reason does not mean that ontology constitutes all of metaphysics;
And that is why that which has been the metaphysics of the West has always remained incomplete and insufficient, also concerning (by the way) another aspect which we will indicate further on.
Being is not really the most universal of all principles, which would necessarily reduce metaphysics to ontology, and (that is so because -) although it [Being] is more primordial than all possible determinations - it is nevertheless already a determination, and every determination is a limitation, at which point the metaphysical point of view cannot be [and should not be] halted.
And (by the way) a principle is obviously less universal the more it is determined, and therefore more relativ; we can [even] say that, on a somewhat mathematical strain, that [every] determining "plus" equals a metaphysical "minus".
This absolute indetermination of the most universal principles, which are therefore those to be considered before all others, is cause for rather great difficulties, not in conception - except maybe for those who are not at all used to this - but at least in the exposition of the metaphysical doctrines, and often one is forced to use only expressions which - in their exterior form - are purely negative.
Such is the case - for example - concerning the idea of Infinity, which in reality is the most positive of all (expressions), because Infinity cannot be other than the absolute all [whole], which - while not being limited by anything - leaves nothing outside itself.
And we have to say that this idea can only be expressed in negative concepts, because in language every direct affirmation is necessarily the affirmation of something, which is to say [it becomes] a particular and determined affirmation; but the negation of a determination or limitation is clearly the negation of a negation, therefore a real affirmation, in the way that the negation of every determination equals basically an absolute and total affirmation.
What we were saying here concerning the idea of Infinity can be equally applied to other extremely important metaphysical concepts, but this example may be enough for what we are about to explain here; and by the way one must never lose sight that pure metaphysics is, in itself, absolutely independent of all those more or less imperfect terminologies which we are trying to reshape, in order to render them more accessible to our understanding. EDH132
René Guénon, Étude Des Doctrines Hindus; Guénon, René EDH131, 132
 Ontology: The branch of metaphysics dealing with the nature of being. Apple Dictionary
 Primordial: Existing at or from the beginning of time; primeval; also: basic and fundamental. Apple Dictionary