Baas van Fraassen

The notion of epistemic community is crucial for the characterization of observability, a cornerstone for Bas van Fraassen’s constructive empiricism. As a matter of fact, observable is, to him, a short for observable-by-us. In this work, it will be shown that the alleged rigidity of the author of The Scientific Image, apparently not very keen to admitting changes in the epistemic community (constituted – according to him – by the human race), is actually an assumption of modesty and good judgment; it means recognizing that scientific enterprise is just a human activity, among many others.

Jago stirs: something is strange. Ice-cold wind streams from the aircon and relentless chatter from the radio:  "…it would not be without reason to deem it a ghost or a phantom formed by the brain…"1 Reality blur: yes, he must have drifted off. Yes, the taxi, but no, why have we stopped? What time is it? He breathes in heavily through the nose. Fog lifting: yes. The guest lecture at the Uni, voices of those students still lashing the insides his skull. Jago searches a foothold for memory. Faint whiff of tiare, plumeria: airport posters with not-so-secret voluptuous bodies. Why is he alone? Or, not exactly alone.

Observation and observability represent a crucial topic in the philosophy of science, as the huge production of papers and books on the subject attests. Philosophy of perception, on the other hand, is a field of study that took root effectively in the last decades. Even then, apparently, the main theories on observation have neglected the issue of determining which is the object of a successful perception. As a consequence, some theses that have recently been proposed are actually paradoxical, despite deriving from renowned and, prima facie, satisfactory and complete theories. This is the situation of van Fraassen’s assertions on the (putative?) observation of images and rainbows (see 2001 and 2008) and of Sorensen’s claims on what one actually sees during a solar eclipse (see 2008). After putting forward a possible characterization of the object of perception, with no need of discussing the issue of intentionality, in this paper it will be shown that devoting adequate attention to this topic, together with acknowledging that observation is an action, in which the subject plays an indeed active role, would make it possible to avoid drawing conclusions that do not seem to be correct, such as the ones just mentioned. Any theory about observation will only be complete and adequate provided the object of perception is taken into account.

Constructive Empiricism, the anti-realist position about science proposed by the Dutch philosopher Bas van Fraassen in 1980, heavily relies upon the distinction between observable and unobservable entities. In 2004 and 2005, F. A. Muller provided a rigorous characterization of observability, later endorsed, apparently, by van Fraassen (cf. Muller & van Fraassen 2008). However, an analysis of what it means to observe is needed to secure Muller’s ‘definition’. Van Fraassen always maintained that observation is an empirical matter, but I argue that a philosophical analysis is also needed and that van Fraassen himself relied on philosophical principles to address the issue of observability.