In defence of strong naturalism - In replying to Perconti’s objection that my strong naturalism implies an unjustifiable materialistic reductionism, I maintain firstly that my materialistic naturalism implies only ontological, not methodological reductionism. Secondly I think that materialism is compatible with the introduction in scientific language of concepts that refer to ficta, that is, to objects that do not exist: in such a way I can preserve the autonomy of mathematics while maintaining that numbers do not exist. Thirdly I suspect that Perconti’s "liberalized" naturalism is not compatible with a truly scientific view of the world. Keywords: Ficta, Materialism, Mind, Naturalism, Ontology, Reductionism.