Ontology or the development of an ontological system is not an end in itself: an ontological system is usually an instrument for other theories or doctrines. Only if a theory or doctrine could not be developed by means of any other ontology would this ontology be basic to it, or an integral part of it. Normally, however, one can translate the one ontological language into the other; for example, realist language into nominalist language, or phenomenalist language into physicalist language, and vice versa. If such a translation is available and does not result in a change in the body of (nonontological) principles of the theory or doctrine itself, then the ontology employed is not fundamental to it. Moreover, the kind of ontological instrument chosen may itself not be appropriately classifiable anymore in traditional terms. As already pointed out, and as will become clearer later, our own ontology is realistic in a sense, but nominalistic in another sense. And as explained above: altho it is certainly not essentialistic in the metaphysical sense, it is fully compatible with a conventionalist form of essentialism, or a form of essentialism in which the notion of an essence would not be more specific than that of a thing.

Since our ontological, conceptual framework is regarded as a mere instrument, not fundamental to the doctrine to be developed, and especially not fundamental to the normative aspects of this doctrine, our attitude towards ontology (and also logics) is instrumentalistic. This does not mean that the system's usefulness would determine some kind of absolute truth; it rather means that the idea that there is and can be only one correct ontological system is rejected altogether. (Strictly speaking, this is a kind of nonmonism which might also be called "pluralism".) We still have to continue our investigation tho in order to make sure that we are not going to work with an inadequate instrument, or an instrument (much) more inadequate than other conceptual tools. It cannot be denied that many specialists in the fields of constructional ontology, logics and related disciplines have wholeheartedly supported other systems or other interpretations of systems for a long time.