This paper examines the is-ought problem on the basis of critical rationalism, the Quine-Duhem thesis, and Bunge's ontology. It reconstructs the dogmatization of Hume's demand for justification into a barrier thesis. The naturalistic fallacy is identified as a special case of the definist fallacy and rejected as a barrier against naturalistic ethics. Values and ought-concepts, construed as categorical, monadic, one-place predicates, are untestable against reality and forfeit their claim to represent it. Existing formal proof attempts hold only within specific systems, disqualifying them as candidates for solving the problem. It shows that no general impossibility proof against is-ought inferences can be provided. The goal-relative ophelic ought-operator is reconstructed as the only known normative operator compatible with reality and ordinary usage. Lineage fitness is reconstructed via evolutionary theory as the non-freely chosen teleonomic ultimate goal of all living systems, from which normative statements follow formally without normative premises. The result is a normative yardstick for rational ethical assessment whose assumptions, derivation, and normative consequences remain equally open to criticism and testable against experience. Eine Deutsche Version kann hier gefunden werden: https://philpapers.org/rec/DELDLD-13
Frieder Sebastian Delor (Sun,) studied this question.