1. Critical Thinking Lesson 6 Learning Objectives: 1. To talk through the mock exam from last week and to look at the correct answers. 1. To be aware of what assumptions are and to be able to identify them. 2. To be aware of what intermediate conclusions are.

2. Mock Results… Have a look at your mark from last lesson. You also have a copy of the mark scheme. We are going to take 10 minutes or so to go through the paper together.

3. Getting Started... What problems can you spot with this argument? Also, what is the reason and what is the conclusion? “The college address is the same street as I’m standing on; therefore, the college must be nearby.”

4. Assumptions An assumption, for the purposes of AS-level Critical Thinking, is an unstated reason. It is something that must be true for an argument to work, but which is not explicitly (clearly) stated in the argument. Our starter argument included an assumption – that the street isn’t very long. It could be that the college is at the other end of a two mile street, in which case it isn’t nearby at all!

5. The Reverse (Negative) Test To test whether something is assumed by an argument, you can use the reverse (negative) test. This involves inserting the opposite of the alleged assumption into the argument and seeing if it still makes sense. For example, to test whether our starter assumes that the street isn’t very long, we would check whether this makes sense: “The college address is the same street as I’m standing on; the street is very long; therefore, the college must be nearby.” With the opposite of the alleged assumption inserted, the argument clearly doesn’t make sense, so the alleged assumption must be true for the argument to work. It is assumed by the original argument.

6. An Example…(from the course pack!) “That boy’s envelope home to parents is addressed to Mr Swale and Dr Swale. Homosexuals must be looking after him.” What is the assumption? The speaker made the assumption that people with doctorates must be male. Use the Reverse Test: The envelope is addressed to Mr Swale and Dr Swale. People with doctorates must be female so homosexuals must be looking after him. This makes no sense, so the original assumption must be true!

7. Task 1 Read through the information handouts. Answer these questions in your own words: 1. Explain what an assumption is. 2. What is the negative test and how does it work? 3. Write your own argument of two sentences or so which includes an assumption. 4. Use the negative test to show what your assumption is.

8. Task 2 Complete the worksheet on assumptions. You will then mark each others’ work using a mark scheme.