Check the direction of a conditional claim before reversing it

A sentence beginning with if can be reversed accidentally during a discussion. The reversed version may sound reasonable while asserting something the original never promised. Check the direction with an invented case before relying on it. This manual exercise concerns known true or false conditions, not an actual approval policy or missing-evidence calculation.

Write one rule and identify its direction

The fictional rule says every ready packet has a completed review. Let P mean the packet is ready and Q mean its review is complete. The stated direction is P implies Q: readiness requires review completion. It does not yet define every condition needed for readiness.

Keep the sentence and the two meanings together in an ordinary document. Avoid using ready, reviewed, and approved interchangeably. Changing a term can change the rule before anyone notices that its direction has also changed.

Test the tempting converse

Consider an invented packet with a completed review that still awaits a required illustration. In this fixture P is false and Q is true. That case is allowed by the original implication: it is not a ready packet lacking review.

The same case contradicts the converse, Q implies P. Review completion does not establish readiness from the original rule alone. Write this countercase beside the proposed reversed sentence. One permitted case is enough to show why the reverse cannot be assumed, without claiming what every real packet requires.

Separate the contrapositive from the inverse

Within the stated two-value rule, not Q implies not P is valid: a packet known to lack completed review cannot be ready under a rule requiring that review. This is the contrapositive, which reverses the direction while negating both conditions.

The inverse, not P implies not Q, is different. The reviewed packet awaiting its illustration is not ready, yet its review is complete. It therefore defeats the inverse as well as the converse. Do not use lack of readiness as evidence that the reviewer failed to finish.

Check necessary and sufficient wording

Under the original rule, completed review is necessary for readiness. Readiness is sufficient to infer completed review within the fictional contract. Completed review alone has not been established as sufficient for readiness; additional requirements may remain.

Ask a second reader to translate those statements back into the P and Q cases. The combination P true and Q false violates the rule. P false and Q true does not. If someone wants the stronger equivalence, ready if and only if reviewed, they need a separately justified rule that supplies both directions. Do not add it by smoothing the wording.

Preserve the evidence boundary

Keep the original statement, permitted countercase, invalid converse and inverse, and valid contrapositive in a direction register. For each proposed inference, name the exact statement that supports it. A confident paraphrase is not another premise.

These examples assume the conditions are known. Unknown review evidence is not the same as known incomplete review, so the contrapositive cannot turn a missing record into a definite readiness result. The finish check is an inference a reader can reconstruct from the declared rule, with stronger claims left unestablished rather than silently imported.