Translating "Only If"
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
"p only if q" means p ⊃ q — the "only if" clause is the consequent.
Show
"You may board only if you hold a ticket" — Board ⊃ Ticket. Not the reverse: a ticket doesn't guarantee boarding.
Watch for
This is video 089's trap wearing propositional clothes. "Only" reverses expectations in both systems.