anti-Realism (or constructive realism) of van Fraasen. He divides his essay into three sections:
An explanation of van Fraasen's attempt to demolish scientific realism
His insistence that van Fraasen succeeds no better than his predecessors in answering a major objection to antirealism
The link between realism and explanation and van Fraasen's attempt to sever that link.
An explanation of van Fraasen's attempt to demolish scientific realism
According to Van Frassen, realism can be defined in the following way: "Science aims to give us, in its theories, a literally true story of what the world is like, and acceptance of the scientific theory involves the belief that it is true." (1088).
Van Fraasen does not go to the extreme, as some do, of rejecting science absolutely. He accepts that scientific statements have a truth value of being true or false. At the same time, however, he rejects the positivist stance where experience is discounted if not in the observable and that only the observable and empirical are considered meaningful and valid. His anti-realism too subsists in the epistemological or methodological level where he thinks that a theory "need not be true to be good" Theories need to be correct as far as observations and experiments go, and this in itself makes it adequate -- even if it does not cohere to positivism (i.e. is not empirically observable). A theory can be unobservable and still be scientifically adequate.
Van Fraasen also distinguishes between realism and strict empiricism. Although both seem similar in that both subsist on observables for testimony, there is a slight difference. Strict empiricism relies on empiricism at all times; realism, however, insists that scientific statements must make sense and have a truth-value whether or not they a reo observable (they aren't always). Realism, accordingly, allows nonevidential or 'metaphysical' arguments to tincture its reasoning.
Sometimes, empirically equivalent but incompatible theories have occurred in real science. For instance, Newton hypothesized that the center of gravity of the solar system is at rest in real space. At the same time, he also said that appearances would be no different if that center were moving through absolute space at any constant velocity. These two theories were claimed by Newton to be empirically equivalent.
Musgrave criticizes Van Fraasen's interpretation of newton's incompatible theories. He does not show that they have ceased to be empirically equivalent.
In several ways, Van Fraasen disputes strict empiricism and shows that it does not make sense or does not exist, but Musgrave criticizes each of these approaches.
Van Fraasen also demolishes the realist by saying that the realist has to forge a link between simplicity and truth for him to accept a theory as true. But this link can only be forged by a metaphysical principle -- which goes against the realist philosophy. And this is the abandonment of strict empiricism.
Musgrave sees the constructive empiricist as being in a better position since he will not be disturbed by the complexities of simplicity, admitting that they are needed for good science to occur, but that the end aim of science is empirical adequacy.
Returning to Van Frassen's anti-realist attempts, Musgrave sees it possible for the realist to destruct them through various means. He does not see why the intrusion of simplicity into the scientific construction of experimentation would harm. This may involve a metaphysical leap, but none the less the focus should be on the pragmatic, and the end result can eventuate in scientific empiricism legitimizing the scientific realist's position.
2. Musgrave's insistence that van Fraasen succeeds no better than his predecessors in answering a major objection to antirealism
Musgrave argues that anti-realists need to distinguish between theory and observation, and that Van Fraasen too errs by equivocating them. If the best explanation is a theory about the observable than theory and observation meet and we can conclude that there is a theory about an observable variable. If however they do not meet, then empirical adequacy and truth collide and we cannot conclude that the best explanation of science coheres to realism, because it actually does not.
Realist ways of thinking and talking are impossible to get away from. The unconscious acceptance of the truth of the statement (the truth value of the scientific statement) and the empirical adequacy of the theory seem to be linked. For instance, as Musgrave points out, van Fraasen talks of detecting an electron in a cloud chamber. Inherent in this statement is his belief that the object really exists, otherwise he would not talk about detecting it. In this way, van Fraasen shows full commitment to the theory of electrons, even though there are various theories of electrons and none has been absolutely accepted. In this way, van Fraasen is, ironically, as realist / empiricist as those whose approach he is trying to demolish.
Finally, Musgrave argues that Van Fraasen fails in demolishing realism since his argument does not make sense and is sometimes incoherent. Van Fraasen says that what is observable by humans is a "functions of facts about us qua organisms in the world" and that it is for science to tell us what is observable and what not (1097) are. Almost any (of not all) theories however necessarily integrate unobservable together with observable aspects and, therefore, van Fraasen would have us accept few if any theories as scientifically valid. The constructive empiricist can only accept a theory if it is empirically adequate, but if a part of this theory is not observable by humans it militates against that which the constructive empiricist can accept. More so, the consistent constructive empiricist cannot accept that anything cannot be observable by humans.
3. The link between realism and explanation and van Fraasen's attempt to sever that link.
Realism and explanation are doubly linked. Realists think that science explains facts about the world, and they think that the realist philosophy of science explains facts about science.
Taking the latter claim first, Realism claims that the only reason that science has had predictive success is because it falls back on realism for its evidence. Van Fraasen however sees the success of one scientific theory over another as rather depending on competition. Only the successful ones thrived, but they did not necessarily need to latch onto realism for survival. It just happened to be that these were the ones that coincided (many times) with observed regularities.
Van Fraasen has, however, not demolished the realist stance. His argument can be accepted by both relists and anti-realists. Certain theories survive. They happen to be demarcated by compliance with observable regularities. Moreover, he says that only successful theories survive, but he does not explain what it is about these theories that make them successful and allow them to survive. He does not answer the point.
We can argue back and forth -- and realist arguments go back a long way -- for what it is that makes one scientific theory more acceptable and recognized than another. This dilemma is called the Ultimate Argument. Van Fraasen -- according to Musgrave -- has not shed a different light on it.
Van Fraasen too attacks the realist demand for explanation; not every theory he says can be presented with an explanation. Some of newton's theories, he claims, come with no explanation. Newton's theory of gravitation, for instance, came only with description (no explanation). And modern physics has the same manifestation.
Musgrave, however, says that van Fraasen conflates realism with essentialism, conflating demanding an explanation with demanding an ultimate explanation. Some things, Musgrave, elaborates, can be explained but in almost every scientific principle, we reach a point where ultimate explanation cannot be gained. Whilst some realists demand that everything be explained, other realists accept that some principles should be accepted as ultimate or self-explanatory. The need for an explanation, therefore, to everything also varies from person to person, each of whom sees things in different ways. According to Musgrave, Essentialism (that there is an essential explanation to everything) and the intuitive feelings behind this should be rejected. Newton propounded this view too. Newton did decline to explain gravity, but this was because he saw it as containing an ultimate explaining in it. Van Fraasen mistakenly calls this "the realist demand for explanation' equivocating, as Musgrave pointed out before, between explanation and essentialism / ultimate explanation.
Musgrave too criticizes van Fraasen for pronouncing that the "interpretation of science and the correct view of its methodology are two separate topics" (1106). To Musgrave, any interpretation of science should harmonize with methodological pronouncements.
According to van Fraasen, good explanations can be underpinned by empirically adequate theories just as well as true ones. He takes a pragmatic -- constructivist -- approach. 'Pragmatic', in philosophical circles, can refer to utterances that are useful; they need not necessarily be true.
Van Fraasen thinks that explanation is highly dependent on its context. It is its context that explains (involves) causality therefore resulting in an explanation. However, the cause also varies enormously with the context, as John Mill says…