LSAT Prep: Conditional Language

Difference between Conditional and Absolute Statements

Absolute asserts facts (Mary is doctor)

Conditional: Provides a hypothesis (If → then statements)

Valid Infereneces

Deductions that follow logically from given premises, ensuring that if the premises are true, the conclusion must also be true.

Invalid Inferences

Deductions that do not logically follow from the premises, meaning that even if the premises are true, the conclusion may be false.

Types of Valid Inferences

1. Valid Affirmations

2. Contrapositive (Switch the statements and negate them)

Types of Invalid Inferences

1. Fallacy of the Converse (Switch the if, then)

2. Fallacy of the Inverse (Negate the if then statements)

Which term is associated with the sufficient condition

If statements

Which term is associated with the necessary conditions

Then statements.

Sufficient or Necessary: If

Sufficient

Sufficient or Necessary: When

Sufficient

Sufficient or Necessary: All

Sufficient

Sufficient or Necessary: Only if

Necessary

Sufficient or Necessary: Only

Necessary

Sufficient or Necessary: Unless

Necessary(Change unless to If Not)if not, the sufficient is false.

Sufficient or Necessary: If and only if

Bi-conditional

How to diagram “No” in a conditional

Use the No Torpedo to negate the sufficient condition.

Ex. No Mathletes have a girlfriend.

If you are a Mathlete, then you have no girlfriend

CP: If you have a girlfriend, then you are not a Mathlete.

Sufficient or Necessary: The only

Sufficient

Sufficient or Necessary: Only

Necessary

Other If Not terms

Without, until, except

Transitive Property

A logical rule stating that if A implies B and B implies C, then A implies C.

Transitive Fallacy

A logical error that occurs when the transitive property is improperly applied, suggesting that if A implies B and B implies C, then A must imply C without sufficient justification.