An Introduction to Critical Thinking and Creativity - always yours

THE DEAR METHOD 117
fluctuation in climate. Sometimes the Earth gets cooler and sometimes it gets
hotter. It just so happens we are in the hotter period but it has little to do with us.
Sometimes we can rule out an alternative theory by getting more evidence. To
decide whether global warming is due to natural climatic fluctuations, scientists
look at historical records and ice core samples to measure the extent of natural
temperature variation in the past and see whether this accounts for recent global
warming, and the conclusion is negative—global warming is due to recent human
activities.
Coming up with alternative theories requires knowledge and imagination, and
the truth might not be obvious. Human beings are often affected by biases, and
they view the world through perspectives they are most attached to. Some people
like to invoke the supernatural whenever there is something that is puzzling—
for example, a butterfly refused to fly away after Daddy passed away so it must
have been his reincarnation. Others like to resort to divine command, such as it is
God's will. Still others like to blame things on their favorite target, saying it is the
fault of the government / the society / my teacher / my parents / my girlfriend,
and so on. Good scientific reasoning requires us to actively challenge our default
explanation. This is not just a matter of being open-minded. We need the courage
to accept that our most favorite or most comfortable point of view might not be
the correct one.
13.1.4 Step 4: Rank the theories and pick the best one
Once we have come up with a list of alternative theories, we can evaluate them
carefully and pick the one that is most plausible. This method of reasoning is
known as inference to the best explanation, which is of the following form:
We have a set of evidence E.
X,Y,Z,... are all theories compatible with E.
X provides the best explanation of E.
X is most likely to be true.
But how do we find out which theory provides the best explanation? The answer
is that we need to appeal to more general theoretical considerations:
13.1.5 Predictive power
Predictive power is about the quantity and quality of the predictions made by a
theory. Quantity is about the number of predictions that can be made. A theory
that generates no prediction at all fails the minimal requirement for a scientific
hypothesis. A claim that cannot be tested can perhaps still be meaningful. It might
even be true. But if we believe the claim, it only can be a matter of faith and not
reason since there is absolutely no evidence to justify the belief.
The quality of prediction is about precision and accuracy. If an astrologist predicts
that an old man is going to die within 20 years on the basis of the position of