Sandra loves everyone who likes hockey. Tom does not like hockey. Therefore, Sandra does not love Tom.
Is the preceding a valid argument? Give reasons for your answer.
The argument is invalid. While we are told how Sandra feels about people who like hockey (she loves all of them), we are given no information about her feelings toward people who do not like hockey. So we cannot determine whether or not Sandra loves Tom unless we are given more information. Maybe she loves everyone who likes hockey *and* some -- or even all -- people who don't. We don't know!
A parallel argument that I think is more obviously false: I love every play by William Shakespeare. "Faust" is not a play by William Shakespeare. Therefore, I do not love "Faust."
Posted by Jyqm
on 2014-01-28 13:03:53