Understanding Formal Logic Basics

Question 1

Define Sufficency

Answer 1

The “sufficient” condition is often introduced by words such as “if,” “when,” and “whenever.”

Something that’s sufficient is enough to get the job done. However, without more info, we can’t assume that it’s a requirement (necessary).

It might help to think of the sufficient condition as “activating” the necessary condition.

Question 2

Define Necessity

Answer 2

The “necessary” condition is often introduced by words such as “then,” “must,” and “required.”

Something that’s necessary has to happen in order for the “sufficient condition” to occur.

However, without more info, we can’t assume that it’s the only thing that has to happen in order to know that the sufficient condition also happened (or will happen).

Question 3

Contrapositive Definition

Answer 3

Flipping Necessity and Sufficiency clauses and negating them, thereby making them equivalent

Question 4

Contrapositive Steps

Answer 4

1) Flip Sufficient
2) Slip Necessity
3) Negate BOTH while also changing or’s to and’s and and’s to or’s