# modal

## Review of K Propositional Rules

Topic
Logical System

There are the ordinary (non-modal) tree propositional rules plus

The Modal Negation (MN) rules

Topic
Logical System

## S4 Propositional Rules

Topic
Logical System

10/7/09

There are the ordinary (non-modal) tree propositional rules plus

The Modal Negation (MN) rules

## K Propositional Rules

Topic
Logical System

There are the ordinary (non-modal) tree propositional rules plus

The Modal Negation (MN) rules

Topic
Logical System

## The Tree Applet for Modal Trees

Topic

7/27/08 10 Software

### Skills to be acquired in this tutorial:

None really: this is merely to give you a whiff of the topic of trees for modal logic.

Colin Howson, [1997] Logic with trees Chapter 12 Section 2

The Howson [1997] does not expand on modal logic (and modal trees) so a text like

Rod Girle [2000] Modal Logics and Philosophy

would definitely be a help here.

## Review of S4 Propositional Rules

Topic
Logical System

10/7/09

There are the ordinary (non-modal) tree propositional rules plus

The Modal Negation (MN) rules

## S4

Topic
Logical System
###### 6/23/12

Rod Girle [2000] Modal Logics and Philosophy Chapter 3

S4 has the rules

{Non-modal propositional rules + Modal Negation + ◊R + □R+ □T+□□R}

These are described in Review of S4 Rules.

The extra rule (over T) is the Rule □□R and what it allows you to do it this. Without it (but with the other rules) you could reason from

□F (n)

## T

Topic
Logical System

10/7/09 10Software

Rod Girle [2000] Modal Logics and Philosophy Chapter 3

T has the rules

{Non-modal propositional rules + Modal Negation + ◊R + □R+ □T}

These are described in Review of T Rules.

## Review of T Propositional Rules

Topic
Logical System

There are the ordinary (non-modal) tree propositional rules plus

The Modal Negation (MN) rules