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Meet the team

Professor Tom Stoneham and Dr Barry Lee are the lead educators on this course. For this run of the course we’re also joined by Dr Rob Trueman. Tom is the …

What is an argument?

Here’s what we’re going to mean by an ‘argument’. What is an argument? An argument is a collection of claims made up of premises and a conclusion. An argument (as …

New connectives and ‘dictionaries’

Last week we began to see how we could use a formal language to clarify and evaluate claims and arguments expressed in a natural language like English. This week we’ll …

Natural Language Challenges

So far, we’ve looked at arguments expressed in an everyday language: English. Logicians, linguists, and philosophers call everyday languages (like English, Swahili, Arabic, and Mandarin) ‘natural’ languages. These are what …

Truth-table shortcuts

There are five basic sentences in our representation of the argument. So a full truth-table would have thirty-two rows. That would be quite a hefty truth-table! But there is a …

A more serious argument: The problem of evil

In this step we’re going to look at a more serious and challenging argument. One reason the argument is challenging is simply the number of basic sentences involved. We’ll look …

Logical equivalence: wedge–arrow

This video shows a truth-table proof of the Wedge–Arrow Law. This law says that ‘(P (rightarrow) Q)’ is logically equivalent to ‘(~P (vee) Q)’.

Logical equivalence: De Morgan’s law

This video gives an example of testing for logical equivalence using a truth-table. In this case, we show that ‘(P & Q)’ is logically equivalent to ‘~(~P (vee) ~Q)’. This …

Another example of testing for validity

This video shows another example of testing for validity using a truth-table. This time looking at an argument involving a conditional. Let’s pick up on a couple of key points …

Testing for validity

In this video, we see how we can test an argument for formal validity using a truth-table. Here’s the truth-table for our representation of the argument: Figure 1. The truth-table …

Welcome to Week 4

In this video, Dr Barry Lee introduces this week’s work on conditionals and on testing for formal validity with truth-tables.

Defining arrow

This video shows how we define the meaning and logical powers of arrow using a truth-table. The remainder of this step introduces further discussion of this connective. Key points about …