I develop a concept of observability that pertains to qualities rather than objects: a quality is observable if it can be registered by human sensation (possibly with the aid of instruments) without involving optional interpretations. This concept supports a better description of observations in science and everyday life than the object-based observability concepts presupposing causal information-transfer from the object to the observer. It also allows a rehabilitation of the traditional empiricist distinction between observations and their interpretations, but without a presumption (...) that observations are infallible. Using this concept of observability, I also propose a re-formulation of constructive empiricism that is easier to defend against realist attacks, while open to reasonable realist intuitions. (shrink)

Martin Kusch has recently defended Bas van Fraassen’s controversial view on microscopes, according to which these devices are not ‘windows on an invisible world’, but rather ‘image generators’. The two authors also claim that, since in a microscopic detection it is not possible to empirically investigate the geometrical relations between all the elements involved, one is entitled to maintain an agnostic stance about the reality of the entity allegedly represented by the produced image. In this paper I argue that, contrary (...) to what Kusch maintains, this might not be a neutral way to render scientific evidence. Moreover, a constructive empiricist can support a realist interpretation of microscopic images. In fact, constructive empiricism and van Fraassen’s own anti-realism do not necessarily amount to the same thing. (shrink)

According to Bas van Fraassen, a postulated entity which can only be detected by means of some instrument should not be considered observable. In this paper I argue that (1) this is not correct; (2) someone can be a constructive empiricist, adhering to van Fraassen’s famous anti-realist position, even admitting that many entities only detectable with a microscope are observable. The case of the paramecium, a very well-known single-celled organism, is particularly instructive in this respect. I maintain that we actually (...) observe paramecia and not just detect them, contrary to what van Fraassen claims. As a matter of fact, even if we can only perceive these protozoans by using a microscope, we are in condition to know that the relevant counterfactual conditions (like the ones Bueno proposed in 2011) are met. Moreover, paramecia satisfy observability and existence criteria proposed by Buekens (1999) and Ghins (2005). But admitting paramecia and the like among the observables does not threaten Constructive Empiricism, for there will always be a line between observables and unobservables on which van Fraassen’s anti-realism can rest. (shrink)

I offer an explicit account of the underdetermination thesis as well as of the many challenges it poses to scientific realism; a way to answer to these challenges is explored and outlined, by shifting attention to the content of theories. I argue that, even if we have solid grounds (as I contend we do) to support that some varieties of the underdetermination thesis are true, scientific realism can still offer an adequate picture of the aims and achievements of science.