Smart Thinking: Skills for Critical Understanding and Writing, 2nd Ed

ANSWERS, DISCUSSION, AND FURTHER ADVICE 167

conclusion as stated involves two elements: a question of trust (and whether

or not politicians lie obviously bears on this question) and a question of the

quality of their decisions (and politicians' knowledge is relevant to this

matter). Relevance is specifically concerned with the relationship between

premise and conclusion.

Exercise 6.3

For each of the four conclusions, here are one relevant and one irrelevant premise
(can you see which is which?):

a 'In a democracy, voting is not just a right but a civic duty' and 'Many
European swallows fly south for the winter'.
b 'Humans can only survive if the environment is well protected' and 'Mining
activities in Australia usually trespass on Aboriginal lands'.
c 'Eighty per cent of the songs on commercial radio come from the USA and
'My family watches The Simpsons every night'.
d 'Personal computers help us to work, study, and relax' and 'There are two
main types of personal computer: the PC and the Macintosh'.
The first premise, in each case, is relevant. Note how all of the premises are
acceptable, even though in some cases they are patently irrelevant (as in exercise 6.3
(a)).
The most important questions to ask yourself after doing this exercise are: Why
do some irrelevant premises appear relevant? What mistakes do we make when we
misjudge relevance? Reflect on these questions and come up with some answers in
relation to an area of knowledge or expertise with which you are familiar.

Exercise 6.4

Looking back to exercise 6.3, I would add the following claims to the premises
given above:

a If something is a duty, then it is acceptable for it to be compulsory.
b Economic development is pointless if humans do not survive,
c American songs are culturally loaded with American values and opinions.
d The help given by a personal computer is only available if you actually own a
personal computer.
Can you see here how errors in relevance are usually associated with picking the
wrong dependent framework premise? When we think that a premise is relevant to
a conclusion and, on reflection, we decide that it is not, usually we are changing
our minds about the framework premise that goes along with it.
Try changing the four premises given in these answers. If you change them
enough, can you make the original four premises from exercise 6.3 irrelevant?
For instance, in example a, if the framework premise was 'Not all duties should