An immediate inference is an inference which can be made from only one statement or proposition. For instance, from the statement "All toads are green." we can make the immediate inference that "No toads are not green." There are a number of immediate inferences which can validly be made using logical operations, the result of which is a logically equivalent statement form to the given statement.

Conversion

• Given a type E statement, from the traditional square of opposition, "No S are P.", one can make the immediate inference that "No P are S" which is the converse of the given statement.
• Given a type I statement, "Some S are P.", one can make the immediate inference that "Some P are S" which is the converse of the given statement.

Obversion

• Given a type A statement, "All S are P.", one can make the immediate inference that "No S are non-P" which is the obverse of the given statement.
• Given a type E statement, "No S are P.", one can make the immediate inference that "All S are non-P" which is the obverse of the given statement.
• Given a type I statement, "Some S are P.", one can make the immediate inference that "Some S are not non-P" which is the obverse of the given statement.
• Given a type O statement, "Some S are not P.", one can make the immediate inference that "Some S are non-P" which is the obverse of the given statement.

Contraposition

• Given a type A statement, "All S are P.", one can make the immediate inference that "All non-P are non-S" which is the contraposition of the given statement.
• Given a type O statement, "Some S are not P.", one can make the immediate inference that "Some non-P are not non-S" which is the contraposition of the given statement.