# propositional

## Tutorial 4: Arguments and searching for a counter example

Topic
Logical System

9/16/12

### Skills to be acquired in this tutorial:

To learn how to symbolize arguments, and how to judge whether they might be invalid using truth-table methods.

### Why this is useful:

We wish to appraise arguments, to do this we have to symbolize them first. Judging the invalidity of arguments by truth-table methods is not particularly important, but it does help to develop skills involving truth and lists of formulas.

Bergmann[2004] The Logic Book Section 3.5.

Help with Tutorial 3, if you need it admin Sat, 01/11/2014 - 01:50
Topic
Logical System

8/29/06

### Tutorial 3 The Main Connective Applet

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## Supplementary: The Paradoxes of Material Implication

Topic
Logical System

1/24/06

eg Lander or Suber

The problem or issue here lies with the truth table for the conditional (or material implication) ⊃

Tutorial 3: Sentences and Truth admin Sat, 01/11/2014 - 01:50
Topic
Logical System

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6/8/07 10Software

### Skills to be acquired in this tutorial:

To learn how compound sentences are true or false depending on the truth or falsity of their component sentences.

## Review

Topic
Logical System

There is the idea of setting up a code or convention or dictionary between atomic propositions and capital letters.

There are compound propositions, each of which has a main connective which connects its components.

There are five propositional logical connectives:

'∼' which translates back to 'it is not the case that...'

'&' which translates back to '... and ...'

'∨' which translates back to '... or ...'

'⊃' which translates back to 'if... then ...'

'≡' which translates back to '... if and only if ...'

## Help with Tutorial 2

Topic
Logical System

8/29/06

### Tutorial 2 Example: How Experts Symbolize

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[This is a film-- press the 'play' symbol.]

## Tutorial 2: Symbolizing compound sentences

Topic
Logical System

9/1/12

### Skills to be acquired in this tutorial:

Symbolizing compound sentences. Learning about logical connectives, and the notion of the main connective. Recognizing different constructions in English which have the same underlying logical form. Paraphrasing the English into a standard form.

### Why this is useful:

It is the next step in learning how to symbolize. Main connectives are very important-- they are central to symbolization, they are central to the semantics, and they are central to derivations.

## Help with Tutorial 1

Topic

### Tutorial 1 Exercise 2

[This is a film-- press the 'play' symbol.]

## Supplementary: Why do logic?

Topic
###### 7/31/08

The very first lesson that we have a right to demand that logic shall teach us is, how to make our ideas clear; and a most important one it is, depreciated only by minds who stand in need of it. To know what we think, to be masters of our own meaning, will make a solid foundation for great and weighty thought. [CS Peirce, How to make our ideas clear]

## Tutorial 1 Introduction, sketch of course, and symbolizing atomic sentences.

Topic
Logical System

### Skills to be acquired in this tutorial:

To become familiar with the notions of argument, valid, invalid, premise, and conclusion. To learn how to symbolize atomic sentences.