Modal Logic

Modal logic 1.3 - a strange property of K

Published: 26 Jan 2013

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Modal logic 1.2 - truth trees for system K

Published: 25 Jan 2013

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Counterpart Theory and Quantified Modal Logic (Lewis)

Published: 21 Feb 2014

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Modal logic 1.4 - truth trees for invalid arguments in K

Published: 01 Feb 2013

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Quine's objections to modal logic 4 - referential opacity

Published: 22 Apr 2013

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Modal logic 2.1 - the systems M, B, S4 & S5

Published: 13 Feb 2013

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Quine's objections to modal logic 3 - extensionality and intensionality

Published: 31 Mar 2013

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Modal logic 1.5a - soundness & completeness

Published: 08 Feb 2013

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Modal logic 2.5 - invalid arguments in normal modal logics

Published: 12 Mar 2013

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Challenging the Unknown Unknown in Epistemic Modal Logic

Published: 13 Apr 2012

Modal logic is a type of formal logic primarily developed in the 1960s that extends classical propositional and predicate logic to include operators expressing modality. Modals — words that express modalities — qualify a statement. For example, the statement "John is happy" might be qualified by saying that John is usually happy, in which case the term "usually" is functioning as a modal. The traditional alethic modalities, or modalities of truth, include possibility ("Possibly, p", "It is possible that p"), necessity ("Necessarily, p", "It is necessary that p"), and impossibility ("It is impossible that p"). Other modalities that have been formalized in modal logic include temporal modalities, or modalities of time (notably, "It was the case that p", "It has always been that p", "It will be that p", "It will always be that p"),deontic modalities (notably, "It is obligatory that p", and "It is permissible that p"), epistemic modalities, or modalities of knowledge ("It is known that p") and doxastic modalities, or modalities of belief ("It is believed that p").

Branches of Mathematics

Pure mathematics

Applied mathematics

Related Topics

Modal logic 0.1 - basic introduction

1. Logic Lecture: Introduction to Modal Logic

2. Logic Lecture: Introduction to Modal Logic - 2

3. Logic Lecture: Introduction to Modal Logic - 3

5. Logic Lecture: Introduction to Modal Logic - 5

Modal Logic (Basics)

Quine's objections to modal logic 2 - use and mention

Quine's objections to modal logic 1 - historical background

A Quick Introduction to Modal Logic, part 1

A Quick Introduction to Modal Logic, part 2

Modal logic 1.1 - system K - introduction

Modal logic 1.5 - logical consequence in K

Modal Logic and Relational Symantics

Logic Lecture: Epistemic Modal Logic and Rumsfeld Known Knowns and Zizek's Unknown Knowns

Modal logic 0.1 - basic introduction

1. Logic Lecture: Introduction to Modal Logic

2. Logic Lecture: Introduction to Modal Logic - 2

3. Logic Lecture: Introduction to Modal Logic - 3

5. Logic Lecture: Introduction to Modal Logic - 5

Modal Logic (Basics)

Quine's objections to modal logic 2 - use and mention

Quine's objections to modal logic 1 - historical background

A Quick Introduction to Modal Logic, part 1

A Quick Introduction to Modal Logic, part 2

Modal logic 1.1 - system K - introduction

Modal logic 1.5 - logical consequence in K

Modal Logic and Relational Symantics

Logic Lecture: Epistemic Modal Logic and Rumsfeld Known Knowns and Zizek's Unknown Knowns

Related Videos

Modal logic 1.3 - a strange property of K

Modal logic 1.2 - truth trees for system K

Counterpart Theory and Quantified Modal Logic (Lewis)

Modal logic 1.4 - truth trees for invalid arguments in K

Quine's objections to modal logic 4 - referential opacity

Modal logic 2.1 - the systems M, B, S4 & S5

Quine's objections to modal logic 3 - extensionality and intensionality

Modal logic 1.5a - soundness & completeness

Modal logic 2.5 - invalid arguments in normal modal logics

Challenging the Unknown Unknown in Epistemic Modal Logic