Purpose of the assignment
You will practice distinguishing logical validity from logical invalidity.
Subject matter
Section 3.3
Tasks
For each of the following examples, decide
- which of the four classical reasoning schemes is used;
- whether the arguments are correct;
- whether the conclusion is correct;
- whether the reasoning is valid or invalid.
Reasoning A
People are mortal.
Dogs are not people.
Conclusion: dogs are not mortal.
Reasoning B
In all American cities there are skyscrapers.
Toronto is an American city.
Conclusion: there are skyscrapers in Toronto.
Reasoning C
All countries that have the euro as their currency are in Europe.
Denmark is not in Europe.
Conclusion: Denmark does not have the euro as its currency.