Scientific realism states that science aims to give us in its theories a literally true story of what the world is like, and acceptance of scientific theory involves the belief that it is true.

Constructive empiricism holds that science aims to give us theories which are empirically adequate; and acceptance of a theory involves a belief only that it is empirically adequate. This is the statement of the anti-realist position that Fraassen advocates.
A theory is empirically adequate iff what it says about the observable things and events in the world is true exactly if it saves the phenomena. Such a theory has at least one model that all the actual phenomena fit inside. So, Fraassen focuses on the epistemic aspect that involves acceptance as the belief that it is true.
Fraassen argues that scientific realism asks us too much. Acceptance involves something weaker such as adequate theory. We have to construe scientific theory literally. Nevertheless, it does not follow that entities postulated by this theory do really exist. Hence, the acceptance involves that empirical theory is adequate, but not literally true.

Arguments in support of scientific realism

(1) Maxwell’s continuum argument

Realists, along with Maxwell, claim that there is no line between observable and non-observable. An object might of course be temporarily unobservable, but could be observed if the circumstances were more favorable. What we see in the microscope is observable. Consequently, what is observable depends on the epistemological capacities we possess.

Fraassen opposes to the Maxwell’s argument. He insists that we can draw a distinction what is observable for us. The human organism is considered as a certain kind of measuring apparatus. Since it has a certain inherent limitations, we can not observe everything. For example, we do not have a direct access to the single carbon atom. Using the microscope, we will not see an actual atom, but an indirect evidence of the electron. Hence, we should suspend judgement about its existence. We should be agnostic whether such entities really do exist. In this case, empirical adequacy is constrained by the human capacity. What is observable by us is true only when we have direct evidence or we can directly see it.

(2) Harman’s Inference to the best explanation

Harman exemplifies inference to the best explanation as an argument in support of scientific realism. He says that to have good reason for holding a theory is to have good reason for holding that the entities postulated by the theory exist.

Fraassen objects to Harman by claiming that we accept a theory, which provides a better explanation, because it gives us empirically adequate explanation. It is a kind of psychological question about what we are willing and unwilling to do.

(3) Smart: correct and useful theories

We might be realists about Copernicus’s theory and anti-realists about Ptolemaic account. The assumption of the realist truth of the Copernican hypothesis explains the instrumental usefulness of the Ptolemaic one, which can produce almost the same predictions about the apparent motions of the planets. Such an explanation of the instrumental usefulness of certain theories would not be possible if all theories were regarded as merely instrumental.

Fraassen argues that this argument is unwarranted. Copernicus’s theory is more useful because it is more empirically adequate than Ptolemaic’s account.

(4) Aqua Regia case

Two samples are dissolved at different rates. It can be explained by appeal to the microstructure. Therefore, we are forced to be scientific realists if we want to explain unobservable phenomena.

Fraassen objects to this argument in the following way. There is an observational law here that appeals to microstructure. It is not the case that we posit this microstructure to explain the phenomenon.

(5) Putnam’s miracle arguement

The enormous success of science can be explained that this science is true. It would be a miracle if it did so well and it would be false. So, we should be scientific realists.

Fraassen argues that the success of science is not a miracle, but it does not follow it is true. We judge this theory by empirically adequate explanation. In an attempt to fit all the actual phenomena, scientists revise the scientific model from time to time. This fact implies that they are looking for the most empirically adequate theory. Consequently, we accept this theory among the many others as one that saves the phenomena best.

Bibliography:

  • Quine, W.V. The Scope and Language of Science, in Reality in Focus: contemporary readings on metaphysics / edited by Paul K. Moser, Prentice-Hall, Inc, 1990
  • Fraassen, Arguments Concerning Scientific Realism, in Reality in Focus: contemporary readings on metaphysics / edited by Paul K. Moser, Prentice-Hall, Inc, 1990
  • Gutting, Gary, Scientific Realism vs. Constructive Empiricism: A Dialogue, in Reality in Focus: contemporary readings on metaphysics / edited by Paul K. Moser, Prentice-Hall, Inc, 1990