Abstract
The dissertation offers a truth-dependent account of scientific progress. First, leading anti-realist descriptions of progress are evaluated. These are the problem-solving approach of Stephen Toulmin and Larry Laudan, the constructive empiricism of Bas van Fraassen and the instrumentalism or pragmatism that is common in psychology and often associated with Hans Eysenck. They are found to be inadequate. A realist alternative is proposed. It is non-monotonic and reckons progress as an increase in the truth content of scientific corpora, where scientific change is recognized as dynamic and more akin to smelting or ore purification than the simple accretion or accumulation that is customary in realist theories. This picture derives support from the "granularity thesis" which says that, given enough time, or large (temporal) granularity, the truth values of several and perhaps many scientific statements can be known with certainty. Further, scientific anticipations and simultaneous discoveries are seen to support the truth-dependent account in several ways. In one, the idea of redundant discovery is expanded in terms of a realist "same-world thesis" in which all discoverers of the same phenomenon or theory may be seen to have discovered truths about a mind-independent world. Second, the idea is used to rebut the historical induction, namely the idea that currently held scientific beliefs will eventually be rejected in much the same way that earlier beliefs were rejected. An appendix discusses the concept of "expertise" in terms of efforts to communicate progress in medicine.