摘要：Scientific theories present descriptions of abstract or ideal systems, according to the semantic view of theories. These ideal system descriptions - commonly called "models" -:-are used to explain systems in the natural world. On the semantic view of theories, scientific explanations have several components: descriptions of the ideal system; the hypothesis that a system in the natural world is isomorphic to or matches the ideal system in some significant aspects; and the specification of the range or scope of natural systems which are to be explained using the model. I believe that the picture presented by the semantic view of the nature and form of empirical claims can help clarify some important disputes in evolutionary theory; empirical evaluation of competing claims presumes agreement and understanding of the exact nature of those claims. I· suggest that the semantic' approach to theories offers a useful framework for sorting out the exact natlll'e of competing claims within several widely-debated areas of evolutionary theory (for a detailed presentation of the semantic view, see Suppes 1957, 1967, van Fraassen 1970, 1972, 1980, and Suppes 1972, 1977; for application of the semantic approach to evolutionary theory, see Beatty 1980, 1981, 1982, Thompson 1983, 1985 and Lloyd 1983,1984).
