Edward MacKinnon

The idea that science aspires to and routinely achieves truths about the world has been challenged in recent writings. Rather than beginning with a theory of scientific development, or of scientific explanation, we begin with a consideration of truth claims in ordinary discourse, particularly with Davidson's truth-functional semantics. Next we consider the way in which some framework features of ordinary language discourse are extended to and modified in scientific discourse. Two areas are treated in more detail: quantum theory, and the peculiar problem of semantic entailment it involves; and quantum field theory. These supply a basis for criticizing some historicist and logicist treatments of the truth of scientific claims

The consistent histories reformulation of quantum mechanics was developed by Robert Griffiths, given a formal logical systematization by Roland Omn\`{e}s, and under the label `decoherent histories', was independently developed by Murray Gell-Mann and James Hartle and extended to quantum cosmology. Criticisms of CH involve issues of meaning, truth, objectivity, and coherence, a mixture of philosophy and physics. We will briefly consider the original formulation of CH and some basic objections. The reply to these objections, like the objections themselves, involves a mixture of physics and philosophy. These replies support an evaluation of the CH formulation as a replacement for the measurement, or orthodox, interpretation.

This article completes the study begun in I by a detailed consideration of errol harris's, "the foundations of metaphysics in science" and by an independent interpretation of the epistemological foundations of scientific theories. This is done in terms of two components labelled 'a physical language' and 'a mathematical language'. A physical language is conceived as a transformed extension of ordinary language which preserves its basic structural principles while modifying its descriptive metaphysics. The relation between such a physical language and a mathematical system is explained by a correspondence between second order physical predicates and first order mathematical predicates