Logical Arguments

Front

What is the Law of Detachment?

Back

The Law of Detachment states that if a conditional statement is true and its hypothesis is true, then the conclusion must also be true.

Front

What is the Law of Syllogism?

Back

The Law of Syllogism allows one to deduce a conclusion from two conditional statements when the conclusion of one statement is the hypothesis of the other.

Front

What is a Contrapositive?

Back

The contrapositive of a statement 'If P, then Q' is 'If not Q, then not P'. It is logically equivalent to the original statement.

Front

What does it mean for an argument to be invalid?

Back

An argument is invalid if the conclusion does not logically follow from the premises, even if the premises are true.

Front

Example of Law of Detachment: If it is sunny, then I will go outside. It is sunny. What can we conclude?

Back

I will go outside.

Front

Example of Law of Syllogism: If it rains, then the ground is wet. If the ground is wet, then the grass is green. What can we conclude?

Back

If it rains, then the grass is green.

Front

What is a conditional statement?

Back

A conditional statement is an 'if-then' statement that expresses a relationship between two propositions.

Front

What is the hypothesis in a conditional statement?

Back

The hypothesis is the part of the conditional statement that follows 'if'.

Front

What is the conclusion in a conditional statement?

Back

The conclusion is the part of the conditional statement that follows 'then'.

Front

How can you identify a valid argument?

Back

A valid argument is one where if the premises are true, the conclusion must also be true.