Logic students sometimes struggle with understanding and remembering immediate inferences. The more opportunities they have to see them used, the more likely they are to grasp them. Consequently, I want to give some examples of immediate inferences used in the Bible. Two equivalent immediate inferences for categorical statements are *obverse *and* contrapositive*.

**Obverse **changes the quality of the statement, and takes the complement of the predicate. It gives equivalent statements for all four forms of categorical statement:

*All S is P ≡ No S is non-P*

*No S is P ≡ All S is non-P*

*Some S is P ≡ Some S is not non-P*

*Some S is not P ≡ Some S is non-P*

Jesus uses the obverse in Mark 2:22, where He says,

“No one pours new wine into old wineskins… No, they pour new wine into new wineskins.”

The obverse is seen more clearly if translated into categorical form:

No new-wine pourers are non-new wineskin users. (No S is non-P)

All new-wine pourers are new wineskin users. (All S is P)

Jesus uses obverse again later in Mark 13:2 when he says,

“Not one stone here will be left on another; every one will be thrown down.”

In categorical form these statements could be written as:

No stones here will be stacked stones. (No S is P)

All stones here will be non-stacked stones. (All S is non-P)

**Contrapositive **switches the subject and predicate of the statement, and changes both to their complements. It gives equivalent statements for universal affirmative and particular negatives:

*All S is P ≡ All non-P is non-S*

*Some S is not P ≡ Some non-P is not non-S*

The contrapositive is used in Proverbs 13:24,

“Whoever spares the rod hates their children, but the one who loves their children is careful to discipline them.”

In categorical form, the contrapositive can be clearly seen:

All non-discipliners are non-children lovers. (All non-P is non S)

All children lovers are discipliners. (All S is P)

Paul uses something like the contrapositive in Romans 11:6 when he argues,

“And if by grace, then it is no longer of works; otherwise grace is no longer grace. But if it is of works, then it is no longer grace; otherwise work is no longer work.”

This is more obviously the contrapositive when the conditional statements are translated into categorical form:

All grace is non-work. (All S is non-P)

All work is non-grace. (All P is non-S)

You can see from these biblical examples that immediate inferences are used as something like single-premise arguments, one statement implying the next.