Abstract
The notion of so-called "postulated ontology" appears in the context of a well-
-known thesis of the underdetermination of scientific theories by empirical data.
It is argued in the paper, that the conviction of the existence of some kind of relation
between a given theory and ontological ideas can be derived from this thesis,
regardless of its particular form. Therefore, certain solutions to classical philosophical
questions can be obtained, in principle, by careful inspection of scientific
achievements. However, if the thesis of underdetermination holds, such philosophical
solutions are not imposed by science itself. In order to arrive at some kind
of ontology based on science, it seems necessary to accept certain philosophical
presuppositions in the first place. This, and the fact that scientific theories change
in time show that although such a kind of ontology is possible, and perhaps desirable,
it can never be ultimate.