Abstract

In two papers in the mid-seventies, Quine has discussed an ontological deba-cle, the reduction of ontology to an ontology of pure sets only. This debacle, which weakened Quine’s interest in ontology, is the natural outcome of on-tological relativity, or, more precisely, the proxy-function argument. It is ex-plained how Quine unavoidably came to this conclusion. Moreover, it is ar-gued that the result is even more damaging for Quine’s philosophy than has hitherto been assumed. It is shown that in addition to an ontological debacle, there is an ideological debacle, reducing the ideology (lexicon) of science to the ideology of set theory. The ideological debacle results from applying ex-tensional substitution of predicates within a scientific theory that is reinter-preted by means of proxy-functions to a theory with a set-theoretic ontology. Though Quine has recognized the possibility of an ideological debacle, his rebuttal is unconvincing. As a result, his tenet of extensionalism is under heavy pressure.