An Introduction to Critical Thinking and Creativity - always yours

CHAPTER 15
REASONING ABOUT CAUSATION
In the last chapter we discussed Mill's methods and their limitations. Here are
some further issues to consider about causation. In many situations, causes are
correlated with their effects. An event C is said to be positively correlated with
E when the presence of C increases the probability that E will also occur. C is
said to be negatively correlated with E when C decreases the probability of E.
If C has no effect on the probability of E, then C is not correlated with E, or C
is independent of E. So for example, the appearance of lightning is positively
correlated with thunder, negatively correlated with a clear sky, and presumably
not at all correlated with the day of the week.
Correlation is about how often two things are associated with each other, so
it is a matter of degree. Lightning is inevitably followed by thunder, 1 and there
is no thunder without lightning. This is 100% or a perfect correlation. Smoking
is positively correlated with lung cancer, but obviously not all smokers will get
cancer. Indeed, a low correlation between two types of events does not rule out
causation in particular instances. A hunter might fail to shoot his prey most of
the time, but when he succeeds his shot will be the cause of the animal's death.
'Although you might be too far away to hear it.
An Introduction to Critical Thinking and Creativity: Think More, Think Better. By Joe Y.F. Lau 133
Copyright © 2011 John Wiley & Sons, Inc.