38 Unit 2 Critical thinking: the basics
Getting it right
Before you can respond critically to an
argument, by evaluating it or by challenging it
with a counter-argument, you need to have a
clear and accurate interpretation, or analysis, of
what the reasoning is. It is no good challenging
an argument if you have misunderstood or
misrepresented it. That is known as attacking a
‘straw man’ (from the stuffed sacks that soldiers
and archers once used for target practice).
What analysis entails is identifying the
parts of the argument and recognising how
they relate to each other, especially how the
reasons relate to the conclusion. One
convenient way to do this is to reconstruct
the argument in a standard form.
The simplest kinds of argument have one or
two reasons followed by the conclusion, and no
other content besides these. In practice such
arguments don’t really need analysing, as their
structure is plain enough already. However, we
will start with simple examples and build up to
more complex, less obvious ones later.Here is an example of everyday reasoning,
which someone might use to persuade
another to hurry.
[1] The train doesn’t leave until 4.24,
but it can take up to 40 minutes to
get to the station, if the traffic’s bad.
It’s 3.30 now. We need to leave for
the station within ten minutes to be
sure of catching the train.How would this argument look in standard
form?Activity
2.5 Analysing arguments
In Chapter 2.3 you were introduced to the idea
of a standard form of argument. In natural
language an argument can be expressed in
many different ways. Standard form shows
what the underlying argument is. If a text
cannot be reduced to a standard form of
argument, we have to question whether it
really is an argument.
In critical thinking we use the same basic
way of formalising arguments as logicians
have used for many centuries: we list the
reasons (or premises), and then the
conclusion. If we use R for ‘reason’ and C for
‘conclusion’ we can say that all arguments
have the form:
R 1 , R 2 , . . . Rn / CThe reasons and conclusion in a standard
argument are all claims. In theory there is no
limit to the number of reasons that can be
given for a conclusion. In practice the number
is usually between one and half-a-dozen.
The relation between the reasons and
conclusion of standard argument is roughly
equivalent to the phrase ‘so’, or ‘... and so.. .’,
which is why inserting ‘so’ or ‘therefore’ into
the text is a clue – though not an infallible
one. What the whole argument states is that
R 1 , R 2 , etc. are true; and that C follows from
them. Or that because R 1 , R 2 , etc. are true, C
must be true as well.
Another way to say this is that C is true as
a consequence of R 1 , R 2 , etc. being true.
Still another way is to say that C can be
inferred from R 1 , R 2 , etc. (Note that it is not
correct to say ‘R 1 , R 2 , etc. infer C.’ Inferences
are always from one or more claims to
another.)