Thinking Skills: Critical Thinking and Problem Solving

(singke) #1

2.3 Argument 31


Obviously [4] is a much stronger argument
than [1]. Whether it actually convinces its
audience will still depend on their willingness
to accept the evidence. But if they understand
and believe the claims you are making, then
it would be irrational of them not to accept
the conclusion also.
Of course, the ‘if’ is a big one. In all
probability the audience from that time would
not accept your claims because they would not
understand them. What could pictures from
space mean to a 14th-century fisherman? They
would lock you up – or worse – and carry on
believing what they had always believed and
could see with their own eyes: a flat Earth
surrounded by flat sea.
This is why ‘claim’ is the right word for the
statements that appear in arguments. Some of
the claims made in an argument may be
known facts, but others may be forecasts,
suggestions, beliefs or opinions. Claims may
also be false. It is perfectly possible to construct
an argument from false claims, either out of
ignorance, or out of deceit. (That is probably
what people hundreds of years ago would have
suspected you of doing, as they slammed the
dungeon door.)
This point is important in understanding
what argument is. An argument presents
reasons and a conclusion. It does not
guarantee that either the reasons or the
conclusion are true. It is still an argument even
if the claims in it turn out to be false.

Grammatical note
It was noted in Chapter 2.1 that claims can
sometimes take the form of rhetorical
questions, or other sentence types:
imperatives, or exclamations. When
reconstructing an argument in which one or
more of the sentences is not a declarative
sentence, but is making a claim nonetheless,
it is good practice to transform it into a
grammatical statement.

true both that ships appear to sink and that
the Earth’s curvature is the reason. But we
know that now independently of the argument.
The single reason given in [1] does not, on its
own, establish its conclusion.


More reasons
For an effective argument we usually need more
than one reason. Imagine you were sent back in
time several hundred years and had to convince
people that the Earth was not flat. What would
you take with you: pictures from space; stories
of people who have sailed round the world?
These would seem like a good start. Armed with
such evidence, you could supplement [1] and
thereby make it stronger, for example:


[4] Ships appear to sink lower and lower the
further they are from land. But they
cannot actually be sinking, or they would
not come back. Also, sailors have proved
that if you set off in one general direction,
for example east or west, and keep going,
you eventually arrive back where you
started from. These facts show that the
Earth cannot be flat. Besides,
photographs have been taken from space
that show the Earth’s curvature.

Here four reasons are given in support of the
conclusion. The conclusion is introduced by
the phrase: ‘These facts show that’, another
way of saying ‘so’. Three of the reasons are
given first; then the conclusion; then a
further, seemingly indisputable, reason. So
the structure of the argument is as follows:


Ships appear to sink as they sail away.
They can’t actually be sinking or they wouldn’t
come back.
Ships sail in one direction but return to their
starting point.
Pictures from space show the curvature of the
Earth.

The Earth cannot be flat.
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