Preface -- I Foundational Issues -- Arguments for Conditional Logics -- The Framework of My Investigation -- Indicative Conditionals -- Counterfactual Conditionals -- Normic Conditionals -- The Generic Case -- The Qualification Problem -- The Propositional Case -- The Role of Normic Conditionals -- Conversational Implicatures -- The Conditional Logic Project in an Interdisciplinary Context and Default Logics -- The Conditional Logic Project in an Interdisciplinary Context -- The Conditional Logic Project -- The Linguistics of Conditionals Project -- The Philosophy of Conditionals Project -- The Psychology of Reasoning Project -- The Non-Monotonic Logic Project -- Non-Monotonic Logics, Defaults Logics, and Conditional Logics -- A Motivation for the Study of Non-Monotonic Logics -- Reiter Defaults -- Default Logics, Non-Monotonic Rules, and Inductive Inferences -- Types of Non-Derivability Conditions and the Rule of Substitution -- Model Theory, Proof Theory, and Axiomatization of Default Logics -- Conditional Logics and Default Logics -- Possible Worlds Semantics and Probabilistic Semantics for Indicative Conditionals: a Survey and a Defense of Possible Worlds Semantics -- Outline of My Defense of Possible Worlds Semantics for Indicative Conditionals and the Core Idea of Chellas-Segerberg Semantics -- Possible Worlds Ordering Semantics for Conditionals: D. Lewis' and Kraus et al.'s Semantics and Related Approaches -- The Ramsey Test, Stalnaker Semantics, and a General Ramsey Test Requirement -- Ramsey's Original Proposal -- Stalnaker's Version of the Ramsey Test -- Stalnaker Models -- Stalnaker Semantics, Set Selection Semantics, and Chellas-Segerberg Semantics -- Contrasting Ramsey Test Interpretations of Conditionals and Ordering Semantics -- Stalnaker Semantics, Conditional Consistency Criteria, and the Principle of Conditional Excluded Middle.

Bennett's Version of the Ramsey Test -- A General Ramsey Test Requirement -- Indicative and Counterfactual Conditionals and Conditional Logics -- Criteria for Distinguishing Indicative and Counterfactual Conditionals -- Bridge Principles and Logics for Indicative and Counterfactual Conditionals -- Subjective and Objective Interpretations of Indicative and Counterfactual Conditionals and the Ramsey Test -- Fundamental Issues of Probabilistic Approaches to Conditional Logic -- Subjective and Objective Probabilistic Semantics and the Principle of Total Evidence -- The Stalnaker Thesis, the Ramsey Test, and Conditional or Non-Conditional Probabilities as Primitive -- Languages of a Probabilistic Conditional Logic -- Further Reasons for the Restriction of Languages of Probabilistic Conditional Logics -- Propositions, NTV (``No Truth Value''), and Conditional Logic Languages -- Adams' Probabilistic P Systems -- The P Systems: Systems P, P*, and P+ -- Threshold Semantics -- Adams' System P and Schurz's Modification -- Possible Worlds Semantics for (Indicative) Conditionals and Quasi Truth Value Assignments in Adams' Probabilistic Semantics -- D. Lewis' Triviality Result and Logics for Indicative Conditionals -- D. Lewis' Triviality Result -- Triviality due to Iterations (and Nestings) of Conditional Formulas -- D. Lewis' Triviality Result, Restrictions of Languages, and Truth Value Accounts of Indicative Conditionals -- Conclusion -- Bennett's Gibbardian Stand-Off Argument -- Bennett's Extended Gibbardian Stand-Off Argument -- A Criticism of Bennett's Gibbardian Stand-Off Argument -- Summary -- Conclusion -- II Formal Results for Chellas-Segerberg Semantics -- Formal Framework -- Why Chellas-Segerberg Semantics? -- Proof-Theoretic Notions -- Languages LCL, LCL-, LrCL, LrCL*, and LrrCL -- Logics -- Non-Monotonicity -- Consistency and Maximality.

A Propositional Basis for Conditional Logics -- System CK -- A Further Axiomatization of System CK -- Model-Theoretic Notions -- Chellas Frames and Chellas Models -- Chellas Models and Frames and Kripke Semantics -- Segerberg Frames and Segerberg Models -- Validity, Logical Consequence, and Satisfiability -- Notions of Frame Correspondence -- Standard and Non-Standard Chellas Models and Segerberg Frames -- Notions of Soundness and Completeness -- Frame Correspondence for a Lattice of Conditional Logics -- Non-Trivial Frame Conditions for a Lattice of Conditional Logics -- The Notions of Trivial and Non-Trivial Frame Conditions -- A Translation Procedure from Axiom Schemata to Trivial Frame Conditions -- A Non-Triviality Criterion -- Chellas Frame Correspondence Proofs -- System P -- Extensions of System P -- Weak Probability Logic (Threshold Logic) -- Monotonic Principles -- Bridge Principles -- Collapse Conditions Material Implication -- Traditional Extensions -- Iteration Principles -- Soundness and Completeness for a Lattice of Conditional Logics -- General Overview -- Focus of the Completeness Proofs -- Proofs for Segerberg Frame Completeness and Chellas Frames Completeness -- Singleton Frames for CS Semantics -- Soundness w.r.t. Classes of Chellas Frames -- Standard Segerberg Frame Completeness -- General Principles -- Canonical Models -- Canonicity Proofs for Individual Principles -- Chellas-Segerberg Semantics for Indicative and Counterfactual Conditionals -- The Basic Chellas-Segerberg Systems (Systems CK and CKR) -- Objective and Subjective Interpretations of Chellas-Segerberg Semantics -- Alternative Axiomatizations of System CKR -- Conditional Logics without Bridge Principles -- System C -- System CL -- System P -- System R -- D. Lewis' System V -- Monotonic Systems without Bridge Principles (Systems CM and M).

Conditional Logics with Bridge Principles -- Adams' System P* -- D. Lewis' System VC -- Stalnaker's System S -- The Material Collapse System MC -- Summary -- Concluding Remarks -- References.