This volume provides the reader with exclusive insights into Ernest Sosa's latest ideas as well as main aspects of his philosophical work of the last 50 years. Ernest Sosa, one of the most distinguished contemporary philosophers, is best known for his ground-breaking work in epistemology, and has also contributed greatly to metaphysics, metaphilosophy and philosophy of language.This book, resulting from the 18th M??nster Lectures in Philosophy, includes an original article by Sosa on his most recent work in epistemology, and seven critical papers that target a wide range of topics from Sosa's oeuvre, as well as Sosa's responses. As regards his epistemology, the issues discussed include his solution of the sceptical problem in his most recent work and the question of how to integrate a sensible account of testimony to Sosa's virtue epistemology. The selected topics from his other fields of inquiry include his view on empirical challenges to human rationality, his defense of the scientific status of philosophy, his concept of causality as considered against the background of the current debate, his suggestion of a middle-way between existential relativism and absolutism and his externalistic internalism in the philosophy of mind and language Preface; Contents; Chapter 1: Knowledge in Action; 1.1 ; 1.2 ; 1.3 ; 1.4 ; 1.5 ; 1.6 ; 1.7 ; 1.8 ; 1.9 ; 1.10 ; 1.11 ; 1.12 ; 1.13 ; 1.14 ; 1.15 ; 1.16 ; 1.17 ; 1.18 ; References; Chapter 2: Manifesting One's Competences Successfully and Aptly: Enough to Beat the Skeptic?; 2.1 Introduction; 2.2 Sosa on Knowledge as a Manifestation of Competences; 2.2.1 What Is a Competence?; 2.2.2 Aptness: The Successful Manifestation of Competences; 2.3 Manifestations and Their Descriptions; 2.3.1 Can Temporally Posterior Second-Order Competence Manifestation Make Prior Acts Apt? 2.3.2 Are Judgments Concerning Aptness Description-Relative?2.4 The Internalist and Skeptical Perspective; 2.4.1 Knowledge for Davidson's Swampman?; 2.4.2 An Infinite Regress?; 2.4.3 Certainty and Confidence; 2.5 Conclusion; References; Chapter 3: Putting Testimony in Its Place; 3.1 Introduction; 3.2 A )Virtue( Theory of Knowledge: Conditions of Adequacy; 3.3 Two Branches of Sosa's Account of Testimonial Knowledge; 3.3.1 The Individualist Branch; 3.3.2 The Collectivist Branch; 3.3.3 Exploring the Issue: The Problem of Incompatibility; 3.4 Balancing Out the Branches 3.4.1 Understanding Aptness: Externalizing and Collectivizing "Proper Trust"3.4.2 Drawing the Bigger Picture: The Place of Testimony Within Three Dimensions of Knowledge; 3.5 A )Better( Account of Testimonial Knowledge: Solving the Problems; References; Chapter 4: Man the Irrational Animal?; 4.1 The Irrationality Thesis; 4.2 The Standard Definition of Rationality; 4.3 Multidimensionality; 4.4 Implicit Indexicality; 4.5 Arationality and Irrationality; 4.6 Conclusion; References; Chapter 5: Yes There Can! Rehabilitating Philosophy as a Scientific Discipline 5.1 Can There Be a Scientific Discipline of Philosophy?5.2 A Specific Objection Against Philosophy as a Scientific Discipline: The Argument from Insufficient Testability; 5.2.1 The Argument from Insufficient Testability; 5.2.2 Sosa's Response; 5.2.3 Problems of Sosa's Response; 5.3 A General Objection Against Philosophy as a Discipline: The Missing Consensus Argument; 5.3.1 The Missing Consensus Argument; 5.3.2 Sosa's Response; 5.3.3 Problems of Sosa's Response; 5.4 Viable Routes to the Rehabilitation of Philosophy as a Scientific Discipline 5.4.1 How to Rebut the Argument from Insufficient Testability5.4.2 How to Rebut the Missing Consensus Argument; 5.5 Conclusion; References; Chapter 6: Causation, Constitution, and Existence; 6.1 Introduction; 6.2 What Is Interlevel Causation?; 6.3 Is Upwards Causation a Distinct Variety of Causation? Sosa's Arguments; 6.4 Argument 1; 6.5 Argument 2; 6.6 Argument 3; 6.7 Argument 4; 6.8 Conclusion; References; Chapter 7: A Snowslide of Entities; 7.1 Sosa's Existential Relativism; 7.2 Indexicalism, Homonymism, Relativism; 7.3 Different Existing Objects or Different Senses of "Existence"?