Feyerabend discusses the picture of the world proposed by the “ontological prejudice”, that asserts the absolute separation between the domain of philosophy, which gives us ontological knowledge of real objects, and the domain of the sciences, which give us mere instrumental knowledge of phenomena. (To take a contemporary example, object-oriented ontology or OOO is a typical example of the ontological prejudice):
According to the ontological prejudice, knowledge is necessarily linked to certainty (PHILOSOPHICAL PAPERS vol 4, page 9).
In his article “Physics and Ontology” (published in 1954), Feyerabend analyses the relation this view posits between the statements of the sciences, which have only predictive value, and their ontological interpretation, provided by philosophy. On this view philosophy is descriptive and realist, whereas science is essentially reductive and instrumental.
For a philosophy based on the ontological prejudice, science has no descriptive value, it does not describe real objects. Physics reduces complex statements to statements about unknown elements, and its laws express experiential connections between those elements. It allows us to predict and to manipulate the phenomena without knowledge of the underlying reality. Philosophy ontologically determines the elements:
It is the task of philosophy to determine the meaning of expressions of the elementary sentences as well as the nature of elements…It is the task of physics to discover useful connections between elements (13).
Ontology on this view is not hypothetical, it provides us with certain knowledge. The ontology of elements is associated with a corresponding theory of meaning. Physics may discover new relations between elements whose nature remains unknown to science, but only philosophy can tell us what the elements are in themselves. One consequence of this view is that there can be no ontological progress by means of the sciences, in particular no ontological consequences can be drawn from physics:
The whole ontology must already be determined. Therefore, no consequences can be deduced from physical theories that were not already known before the establishment of the theories (13).
A second consequence is that the meaning of scientific statements is fixed in advance by ontology. Theory change does not imply meaning change, as meanings remain stable. This stability of meaning is ensured by the demarcation between science and ontology. Science expresses instrumental and predictive regularities, ontology indicates meaning in terms of the real elements it posits.
Thus the epistemological demarcation between science and ontology is founded on an ontological barrier. The elements are situated behind an impenetrable border (in OOO terms, behind the veil of withdrawal):
We have a series of elementary sentences E1, E2, … En; by mapping the theory to these elementary sentences we obtain a series of other elementary sentences, F1, F2, … Fn. We test the usefulness of the theory by checking whether the situations described by the generated sentences are actually the case (see the sketch below).
Given the absolute demarcation between science and philosophy posited by the ontological prejudice and the stability of meaning it ensures, Feyerabend remarks that the the frontier between them allows no interaction:
Border B is impenetrable. No communication occurs between the field of physics and the field of philosophy (13-14).
In the picture founded on the ontological prejudice, philosophy deals with the real, physics with the phenomena.This prejudice is still with us today, for example in Graham Harman’s object-oriented philosophy. The picture of the relation between science and philosophy in his book THE THIRD TABLE (see my review here) is a typical example of the ontological prejudice. We could say that already in 1954 Feyerabend foresaw OOO and refuted it, in his article “Physics and Ontology”.
Another feature of views based on the ontological prejudice is that we cannot follow any of the methods of science to attain ontological knowledge of reality, but we must make use of a radically different method. Scientific “knowledge”, being mere opinion, may be attained by experiment combined with speculation, but philosophy possesses a sui generis method: intellectual intuition. Only in this way can certainty of knowledge and stability of meaning be assured.