In this essay I am concerned with the problem of conceptual change. There are, needless to say, many ways to approach the issue. But, as I see it, the problem reduces to showing how present and future systems of thought are the rational extensions of prior ones. This goal may not be attainable. Kuhn, for example, suggests that change is mainly a function of socio-economic pressures (taken broadly). But there are some who believe that a case can be made for the rationality of change, especially in science. Wilfrid Sellars is one of those. While Sellars has developed a full account of the issues involved in solving the problem of conceptual change, he is also a very difficult philosopher to discuss. The difficulty stems from the fact that he is a philosopher in the very best sense of the word. First, he performs the tasks of analyzing alternative views with both finesse and insight, dialectically laying bare the essentials of problems and the inadequacies of previous proposals. Secondly, he is a systematic philosopher. That is, he is concerned to elaborate a system of philosophical thought in the grand tradition stretching from Plato to White head. Now with all of this to his credit, it would appear that there is no difficulty at all, one should simply treat him like all the others, if he indeed follows in the footsteps of past builders of philosophic systems.

Inhalt
I/Pictures and Teleology.- 1. Science, Philosophy, and Change.- 2. Images.- 3. Pictures and Coherent Images.- 4. Truth and Explanation.- 5. Explanationism.- II/Rules of Inference, Induction, and Ampliative Frameworks.- 1. Ampliative Inference.- 2. Sellarsian Rules of Inference.- 3. Goodman on Induction and the Scientific Framework.- 4. Quine, Induction, and Natural Kinds.- 5. Conclusion.- III/Induction and Justification.- 1. Introduction.- 2. Rules, Theories, and Conceptual Frameworks.- 3. Justification, Probability, and Acceptance.- 4. The Meaning of 'Probable'.- 5. 'Probable' Versus the Ground-Consequence Relation.- 6. The Purpose of Probability Arguments.- 7. Practical Reasoning.- 8. Modes of Probability.- IV/Theories.- 1. Introduction.- 2. The Sellarsian View of a Theory; an Introduction.- 3. Sellars and Nagel on the Formal Structure of Theories.- 4. The Observation Framework.- 5. Correspondence Rules (C-Rules).- 6. Explanation.- 7. Ontological Preliminaries.- 8. Explanation and Existence.- 9. Explanation and Two Senses of 'About'.- 10. Explanation Versus Derivation.- 11. The Theoretician's Dilemma and the Levels Theory of Theories.- 12. Sellarsian Systematization.- 13. Explanation and Existence: The Role of C-Rules.- V/Conceptual Change.- 1. Introduction.- 2. The Scientific Image: a Reconsideration.- 3. Ontological Necessity.- 4. Reasonableness and Rationality.- 5. Conceptual Change.- 6. Rationality Versus Reasonableness.- Notes.- Index of Names.- Index of Subjects.