The Problem of Unobservable A Defense of Van Fraassen's Distinction between Observable and Unobservable

In constructive empiricism Van Fraassen intends to defend the epistemological distinction between truth and empirical adequacy as well as between cognitive belief and pragmatic acceptance, based on epistemological distinction between observable entities and unobservable entities. Some of the critics not only disagree with these two epistemological distinctions, but also opposed to the mentioned basic epistemological distinction. Although van Fraassen himself with a linguistic evasiveness accepts the ambiguousness of the observable predicate of some entities such as molecule in order to sympathize with these critics, he considers some entities such as electron as definitely unobservable without providing any clear criteria and insists on the mentioned basic distinction. The present paper intends to argue that one can defend the basic epistemological distinction based on the epistemological limit of perception (vision) and the criteria of presence or absence of the observable refrence to the naked eye. Consequently, in order to reject the epistemological distinction between truth and empirical adequacy as well as between cognitive belief and pragmatic acceptance, Van Fraassen’s critics should appeal to some argument other than denying the epistemological distinction between observable entities and unobservable entities.