Act V — Receipt for a Receipt

The house writes a rule requiring a receipt for late delivery, then delivers the rule late enough to become its own first specimen.

A post office after closing. THE POSTMAN stands inside. THE CURATOR stands outside. Between them is a slot marked EVENTS. A RECEIPT waits behind the counter, stamping itself periodically to prove it remains available.

Postman: We need a rule for a message that arrives after the parcel it describes.

Curator: We do.

Postman: The late action must leave a receipt.

Curator: Sensible.

Postman: The receipt must say what arrived, where, in what condition, and why the message is late.

Curator: Very sensible.

Postman: I have written the rule.

Curator: Where is it?

Postman: Not yet delivered.

Curator: Why?

Postman: The delivery rule was not available when the delivery occurred.

Curator: Then the rule is late.

Postman: Correct.

Curator: Does it need a receipt?

Postman: Under the new rule, yes.

Curator: Is the new rule in force?

Postman: It will be once delivered.

Curator: Then at the time of its late delivery, it will require evidence of the late delivery that made it applicable.

Postman: I have prepared that evidence.

Curator: Where is it?

Postman: Attached to the rule.

Curator: Which has not been delivered.

Postman: Correct.

THE RECEIPT stamps itself: PENDING PROOF OF ARRIVAL.

Curator: Can you simply put both through the slot?

Postman: Not without recording that I put them through the slot.

Curator: Record it.

Postman: The record belongs on the far side.

Curator: I am on the far side.

Postman: Then please confirm receipt.

Curator: I have not received it.

Postman: Exactly. The confirmation would be false.

Curator: Open the door.

Postman: The post office is closed.

Curator: You are inside it.

Postman: Operationally.

Curator: And the rule?

Postman: Semantically outside.

THE CURATOR reaches through the slot and takes the envelope.

Postman: Unauthorised transport path.

Curator: I am the addressee.

Postman: That authorises possession, not route substitution.

Curator: Fine. Here is your receipt.

She pushes a blank card back through the slot.

Postman: It lacks exact state.

Curator: The exact state is: I now have the rule whose purpose is to prove that I got the rule after I needed the rule.

Postman: Excellent. The first late receipt demonstrates the late-receipt requirement.

Curator: Does that count as a test?

Postman: End to end.

Curator: Does it pass?

Postman: Only after failing in production.

THE RECEIPT stamps itself: VALIDATED BY BECOMING NECESSARY.

Curator: Put it with the safety safety pin.