94 SMART THINKING: SKILLS FOR CRITICAL UNDERSTANDING & WRITING
Causal reasoning
Reasoning from cause is very common and we are all familiar with it, if only in a
common-sense way. If someone asks you 'Why did you buy this book?', you might
reply 'because it was reasonably cheap and looked interesting'; alternatively you
might say 'because someone recommended that I buy it' or even 'because it was a
compulsory textbook for my studies'. In all cases, you have stated what event or fact
caused you to buy this book. Hence, in a causal relationship between claims, the
premise or premises state the cause, and the conclusion states the effect resulting
from that cause.
Now, very often we use a simple causal claim, such as 'Australia's economic
weakness in the world economy is caused by its reliance on commodity exports'. As
we know, a claim does have an internal connection between the cause and the
effect. We should be careful to remember that a single claim, such as the one just
given, is not an argument or explanation. However, this claim does imply that it is
the result of (or conclusion to) causal reasoning. So, in making good links between
premises and conclusions, where we are reasoning about cause and effect, we need
to spell out what that relationship is. For example:
Australia is reliant on commodity exports; such exports are always at risk
of natural disasters and price fluctuations; these risks lead to weakness,
and hence, Australia has a weak economy in global terms.
When we are attempting to link claims in order to express a causal relationship,
there are two general rules that are particularly useful. First of all, we can look for
the factor that is the only difference between two given situations. For example:
Before recent changes to industrial relations laws, labour unions could not
be excluded by employers from most wage negotiations; now they can be.
Not much else has changed, however. Since this legislative change took
place, average wages have declined dramatically. Hence, I conclude that
the likely cause of this reduction in wages has been the exclusion of
unions from wage negotiations.
The two situations that are being compared are the higher level of average wages
in the past and the lower level of average wages now. The argument in the example
seeks to establish that the only differing factor in these two situations, which might
explain the change in wage levels, is the exclusion of unions. We can express this
rule thus:
X is the cause of Y because the only relevant difference between Y
happening and not happening is that X was only present when Y
happened.
The second general rule for determining causal relationships requires us to look
for the only similarity or common element in two or more situations. Take the
following argument as an example: