Constructive Empiricism, Observability, and Three Kinds of Ontological Commitment

In this paper, I argue against constructive empiricism that, as far as science is concerned, observability is not an adequate criterion as a guidance of cautious ontological commitment. My argument is in two stages. First, I argue that constructive empiricist choice of observability as a criterion for ontological commitment is based on the assumption that belief in the existence of unobservable entities is unreasonable because belief in the existence of an entity can only be vindicated by its observation. Second, I argue that the kind of ontological commitment that is under consideration when accepting a theory is commitment to what I call a theoretical kind and that observation can vindicate commitment to kinds only in exceptional cases