The following quotes are taken from Introduction to the Study of the Hindu Doctrines by Rene Guenon. They characterize the nature of the metaphysical enterprise.

Always and Everywhere

The object [of metaphysical knowledge] must always be absolutely the same and can in no way be something that changes or that is subject to the influences of time and place. [That is, it is true always and everywhere.]

Completeness

It is absolutely impossible to make any ‘discoveries’ in metaphysics, for in a type of knowledge which calls for the use of no specialized or external means of investigation, all that is capable of being known may have been known by certain persons at any and every period; and this in fact emerges clearly from a profound study of the traditional metaphysical doctrines.

Immutability

The metaphysical point of view is radically opposed to the historical point of view, or what passes for such, and this opposition will be seen to amount not only to a question of method, but also, what is far more important, to a real question of principle, since the metaphysical point of view, in its essential immutability, is the very negation of the notions of evolution and progress.

Certitude

No notice must be taken of contingencies such as individual influences, which are strictly non-existent from this point of view and cannot affect the doctrine in any way; the latter, being of the universal order, is thereby essentially supra-individual, and necessarily remains untouched by such influences. Even circumstances of time and space, we must repeat, can only affect the outward expression but not the essence of the doctrine; moreover there can be no question here, as there is in the relative and contingent order, of beliefs or opinions; metaphysical knowledge essentially implies permanent and changeless certitude.

Uncontestable

Metaphysics of necessity excludes every conception of a hypothetical character, whence it follows that metaphysical truths, in themselves, cannot in any way be contestable. Consequently, if there sometimes is occasion for discussion and controversy, this only happens as a result of a defect in exposition or of an imperfect comprehension of those truths.

Ineffability

Every exposition possible [of metaphysics] is necessarily defective, because metaphysical conceptions, by reason of their universality, can never be completely expressed, nor even imagined, since their essence is attainable by the pure and formless intelligence alone; they vastly exceed all possible forms, especially the formulas in which language tries to enclose them, which are always inadequate and tend to restrict their scope and therefore to distort them.

Knowledge of the Universal

Knowledge belonging to the universal order of necessity lies beyond all the distinctions that condition the knowledge of individual things. The object of metaphysics is in no way comparable to the particular object of any other kind of knowledge whatsoever.

Being and knowledge are unified

When one speaks of the means of attaining metaphysical knowledge, it is evident that such means can only be one and the same thing as knowledge itself, in which subject and object are essentially unified. [That is, metaphysical knowledge is possible only with a change in one’s level of being or state of consciousness.]

Non-discursive

The means [of achieving metaphysical knowledge] cannot in any way resemble the exercise of a discursive faculty such as individual human reason.

Beyond Rational

We are dealing with the supra-individual and consequently with the supra rational order, which does not in any way mean the irrational: metaphysics cannot contradict reason, but it stands above reason, which is only a secondary means for the formulation and external expression of truths that lie beyond its province and outside its scope.

Intuition

Metaphysical truths can only be conceived by the use of a faculty that does not belong to the individual order, and that, because of the immediate character of its operation, may be called intuitive.

Direct knowledge of principles

The intellect is that faculty which possesses a direct knowledge of principles.

Truer than science

Aristotle declares that “the intellect is truer than science”, which amounts to saying that it is truer than the reason which constructs that science.

Infallible

It is necessarily infallible because of the fact that its operation is immediate and, not being really distinct from its object, it is identified with the truth itself.