Exam 1: Basic Concepts

A term is a word or phrase that stands for a class of things.

All

An argument's conclusion is affirmed on the basis of its premises.

In "If Suzie goes to the party, then John will go," the antecedent is "Suzie goes to the party."

Any argument that is a substitution instance of affirming the consequent is a valid argument.

All weak arguments are uncogent.

A disjunctive syllogism has the following form:

If the following argument is an instance of one of the "famous" argument forms, name the form and indicate whether the form is valid or invalid; if the argument is NOT an instance of one of the "famous" forms, simply write "unnamed form." If Susan lacks the nerve to tell Stephen what she thinks of him, then I should quit my job immediately. But Susan does not lack the nerve to tell Stephen what she thinks of him, so I shouldn't quit my job immediately.

"Go to your room!" This is

Use a counterexample to show that the following argument is invalid. (Remember, it is usually best to use terms-or statements-whose interrelations are well known.) "Some pets are collies. Some collies are dogs. So, some pets are dogs."

All weak arguments have false conclusions.

"Eat your vegetables." This is

When "or" is taken in the exclusive sense, the statement "We'll go swimming or hiking" says what?

All arguments have more than one premise.

Identify the following as valid, invalid, strong, or weak: "Assuming Betty's flight leaves on time, she will arrive in Seattle at 6:00 p.m. Betty's flight did leave on time, so she will arrive in Seattle at 6:00 p.m."

"Chocolate ice cream is better than strawberry." This is

An argument that results from uniformly replacing letters in an argument form with terms or statements is a substitution instance of that form.

No cogent arguments have false conclusions.

Identify the following as valid, invalid, strong, or weak: "60 percent of Volvos ever made are still running. ∴ My father's Volvo still runs."

Use a counterexample to show that the following argument is invalid. (Remember, it is usually best to use terms-or statements-whose interrelations are well known.) "Sue is a physician. So, either Sue is a physician or Sue is a politician, but not both."