CRITICAL THINKING
EXERCISE 1: DETECTING VALIDITY
All laptops are computers. Therefore, all computers are laptops.
All laptops are computers. I don’t have a computer. Therefore, I have a
laptop.
All cellphones with GreenFang technology can send and receive data to
and from laptops that have GreenFang technology. I have a telephone with
Green Fang technology. I will be able to send this snapshot to your laptop.
All cellphones with GreenFang technology can send and receive data to
and from laptops that have GreenFang technology. My laptop doesn’t have
GreenFang technology. Therefore, I won’t be able to send the letter I wrote
on my laptop to your cellphone.
All functional GreenFang cell phones can take photographs. My
GreenFang cell phone is functional. Therefore, I can take photographs with
my phone.
All functional GreenFang cell phones can take photographs. My cell
phone is a BigSmile phone. Therefore, I can’t take photographs with my
cell phone.