An Introduction to Critical Thinking and Creativity - always yours

EXERCISES 67
k) Nothing is impossible.
It is not the case that everything is impossible.
7.2 Determine the consistency of each set of statements below.
a) John has a new secondhand car.
b) All puddings are nice.
This dish is a pudding.
No nice thing is wholesome.
This dish is wholesome.
c) If he is guilty, then his DNA will be on this shirt.
If he is guilty, then he was not wearing a shirt.
If he was not wearing a shirt, then his DNA won't be on this shirt.
d) We are fascinated with being wrong. It teaches us about ourselves. Not
only are there things we don't know, but the things we do know can be
wrong. (Hawking et al., 2003)
e) I would never get AIDS. But it somehow happened, and it was only because
I was unlucky.
f) All events are caused.
Human actions are events.
Human actions are free actions.
No event that is caused is a free action.
7.3 See if these sentences are ambiguous. If so, rewrite them to make explicit
the different interpretations.
a) Only Intel processors, memory chips, and motherboards will be sold.
b) I shall visit Sophie and you will visit Sandra or he will visit Sonia.
7.4 Negation can be expressed in many different ways. Rewrite these sentences
into logically equivalent ones that start with "It is not the case that."
a) Hang gliding is not dangerous.
b) I am unafraid.
c) Belching is impolite.
d) You aren't Einstein.
7.5 Disjunction connects not just sentences, but often phrases as well. They can
also be understood in the exclusive or inclusive sense. See which interpretation is
better for the statements below:
a) Come to the party if you know the bride or the groom.
b) For your next appointment, the doctor will see you on either Tuesday or
Wednesday.
7.6 M Here are some famous quotes from the legendary U.S. baseball player
Yogi Berra. Why are they funny?
a) Baseball is 90 percent mental and the other half is physical.
b) Nobody goes there anymore. It's too crowded.
c) You can observe a lot by watching.