86 SMART THINKING: SKILLS FOR CRITICAL UNDERSTANDING & WRITING
Issues of scope and certainty are also important in reasoning from generalisation.
The purpose of linking together a particular case with a general rule in the premises
is to then draw a conclusion about that specific case based on the generalisation.
The scope of the conclusion, therefore, must be coherent with the generalisation.
The following example shows good coherence:
The incidence of major earthquakes in areas located away from major
tectonic fault-lines is low; Australia is such an area, and hence we can
predict that Australia will rarely suffer from major earthquakes.
However, another example demonstrates poor coherence:
Generally speaking, students at Australian universities receive a high-quality
education. Ho Ming intends to study at the University of Melbourne and fears
that he will not receive a high-quality education.
On the basis of the premise, Ho is wrong to hold these fears.Exercise 6.7
Look at the following conclusions. Without thinking about whether they are true, and
thinking only about the words as they appear in front of you (especially those that
define the scope and certainty of the conclusion), indicate which conclusions are
milder and which are stronger (in relation to one another). Then think about the sorts
of audiences that would need more or less argument to persuade them. Who would
easily be persuaded of the conclusions? Who would be sceptical of these conclusions?
a. All Australians should be forced to do national military service.
b. One option is to consider limited military service for some young Australians.
c. We should definitely establish an inquiry to consider the possibility of
introducing national military service.Review
Effective reasoning requires that we attend to a wide variety of factors, both
in our analysis of the connections between claims and then in the presenta-
tion of those claims and connections. We cannot, truly, separate out the needs
of effective analysis and presentation, since our analysis will always be influ-
enced by the context in which reasoning occurs, and that context is, by and
large, determined by the knowledge and expectations of our likely audience.
Some of the ways to be more effective in reasoning concern the links
between premises: if we make these links well, unpacking any initial 'reason'
for a conclusion into a clear chain of dependent premises, then our analysis
has depth. In particular, we must avoid allowing any claims that are doubtful
to remain implicit, or failing to make explicit links between claims that are not
obvious; such assumptions can only be tested if we are explicit about all the