Critical Thinking Assessment

General directions

• This assessment task consists of five questions and is worth 15% of the final grade.
• Word limit: Approximately 300 words.
• Please submit your answers on MOODLE.

Deductive validity

For each of the following short arguments; (a) say whether the argument is deductively valid or invalid. Then (b) if you think the argument is invalid, explain why the argument is invalid - that is, explain how it is possible for the premises to all be true and the conclusion false. 1f you think the argument is valid, then represent the logical form of the argument, making sure you indicate what your schematic letters (A, B etc) stand for.

(1) The extinction of the dinosaurs 65 million years ago was due either to a meteorite impact or to massive volcanic eruptions. Since the meteorite impact theory can now be ruled out, it must have been the volcanic eruptions that caused the dinosaurs to die out.

(2) All famous movie stars are wealthy. Rose Middleton is wealthy, therefore Rose Middleton is a famous movie star.

(3) 1f killing a human being is always morally wrong, then the death penalty cannot be justified. But there are some situations, such as self=defence, in which it would not be wrong to kill a human being. So the death penalty is justified.

(4) The potato salad will turn out well if you do exactly what my grandmother's recipe tells you to do. The potato salad did not turn out well. So you didn't follow my grandmother's recipe exactly.

(5) People will not participate fully in the political life of their country unless voting is compulsory. Since voting is not compulsory in the UK, the citizens of that country will not fully participate in the political life of their country.